DNA encoding human α1 adrenegric receptors and uses thereof

ABSTRACT

This invention provides an isolated nucleic acid molecule encoding a human α 1a  adrenergic receptor, an isolated nucleic acid molecule encoding a human α 1b  adrenergic receptor and an isolated nucleic acid molecule encoding a human α 1c  adrenergic receptor, an isolated protein which is a human α 1a  adrenergic receptor, an isolated protein which is α 1b  adrenergic receptor and a isolated protein which is a human α 1c  adrenergic receptor, vectors comprising an isolated nucleic acid molecule encoding a human α 1a  adrenergic receptor, vectors comprising an isolated nucleic acid molecule encoding a human α 1b  adrenergic receptor, and vectors comprising an isolated nucleic acid molecule encoding a human α 1c  adrenergic receptor, mammalian cells comprising such vectors, antibodies directed to the human α 1a  adrenergic receptor, antibodies directed to the human α 1b  adrenergic receptor, and antibodies directed to the human α 1c  adrenergic receptor, nucleic acid probes useful for detecting nucleic acid encoding a human α 1a  adrenergic receptor, nucleic acid probes useful for detecting nucleic acid encoding a human α 1b  adrenergic receptor, and nucleic acid probes useful for detecting nucleic acid encoding a human α 1c  adrenergic receptor, antisense oligonucleotides complementary to any sequences of a nucleic acid molecule which encodes a human α 1a  adrenergic receptor, antisense oligonucleotides complementary to any sequences of a nucleic acid molecule which encodes a human α 1b  adrenergic receptor, and antisense oligonucleotides complementary to any sequences of a nucleic acid molecule which encodes a human α 1c  adrenergic receptor, pharmaceutical compounds related to the human α 1a  adrenergic receptor, pharmaceutical compounds related to the human α 1b  adrenergic receptors, and pharmaceutical compounds related to the human α 1c  adrenergic receptors, and nonhuman transgenic animals which express DNA encoding a normal or a mutant human α 1a  adrenergic receptor, nonhuman transgenic animals which express DNA encoding a normal or a mutant mammalian human α 1b  adrenergic receptor, and nonhuman transgenic animals which express DNA encoding a normal or a mutant mammalian human α 1c  adrenergic receptor. This invention further provides methods for determining ligand binding, detecting expression, drug screening, and treatments for alleviating abnormalities associated with human α 1a , α 1b  and α 1c  adrenergic receptors.

This is a continuation of application Ser. No. 07/925,798, now abandoned, filed Sept. 25, 1992.

BACKGROUND OF THE INVENTION

Throughout this application various publications are referred to by partial citations within parenthesis. Full citations for these publications may be found at the end of the specification immediately preceding the claims. The disclosures of these publications, in their entireties, are hereby incorporated by reference into this application in order to more fully describe the state of the art to which this invention pertains.

Although adrenergic receptors (ARs) bind the same endogenous catecholamines (epinephrine and norepinephrine, NE) their physiological as well as pharmacological specificity is markedly diverse. This diversity is due primarily to the existence of at least nine different proteins encoding three distinct adrenergic receptors types (α₁, α2, and β). These proteins belong to the super-family of G-protein coupled receptors, and are characterized by a single polypeptide chain which span the plasma membrane seven times, with an extracellular amino terminus, and a cytoplasmic carboxyl terminus. The molecular cloning of three genes encoding α₁ -ARs supports the existence of pharmacologically and anatomically distinct α₁ -receptor subtypes. The α_(1b) -receptor was originally cloned from a hamster smooth muscle cell line cDNA library, and encodes a 515 a.a. peptide that shows 42-47% homology with other ARs. The message for the α_(1b) -receptor is abundant in rat liver, heart, cerebral cortex and kidney, and its gene was localized to human chromosome 5 (4). A second cDNA clone from a bovine brain library was found which encoded a 466-residue polypeptide with 72% homology to the α_(1b) -AR gene. It was further distinguished from α_(1b) by the finding that its expression was restricted to human hippocampus, and by its localization to human chromosome 8 and it has been designated as the α_(1c) -AR (20). The cloning of an α_(1a) -AR has been reported recently. This gene, isolated from a rat brain cDNA library, encodes a 560-residue polypeptide that shows 73% homology with the hamster α_(1b) -receptor. The message for this subtype is abundant in rat vas deferens, aorta, cerebral cortex and hippocampus, and its gene has been localized to human chromosome 5 (12).

Pharmacological studies have demonstrated the existence of two α₁ -adrenergic receptor subtypes. The studies of α₁ -AR-mediated responses in vascular tissue suggested the possible existence of receptor subtypes, based on the potency and efficacy of adrenergic agonists, as well as differential sensitivity of α₁ receptor-mediated responses to extracellular calcium and calcium channel blockers (6, 24). Although radioligand binding studies of brain α₁ -ARs with either [³ H]WB4101 and [³ H]prazosin showed good agreement with the potency of α-adrenergic antagonists on vascular responses (23, 10), subsequent binding studies of rat brain α₁ -ARs provided strong evidence for the existence of receptor heterogeneity, based on the relative affinities for prazosin and WB4101 (15). These observations were supported by the finding that chloroethylclonidine (CEC) inactivated 50% of the α₁ sites from rat cerebral cortex and 80% of the binding sites from liver or spleen (α_(1b)), but did not inactivate α₁ -receptors from the hippocampus or vas deferens (α_(1a)) (14). Taken together, these results suggested a classification of the α_(1a) -subtype as high affinity for WB4101 and insensitive to alkylation by CEC, and α_(1b) -subtype as 10 to 20 fold lower affinity for WB4101, but sensitive to inactivation by CEC. Consistent with this evidence the transfection of the hamster α_(1b) gene into COS-7 cells induced the expression of an α1-receptor with high affinity for WB4101, 95% of which could be inactivated by CEC. Conversely, upon expression of the rat α_(1a) receptor gene in COS-7 cells, it showed a 10-fold higher affinity for WB4101 than the α_(1b) -receptor, and the binding site was resistant to inactivation by CEC. The existence of the α_(1c) receptor was not predicted from pharmacological data and upon expression it showed 16 and 30 fold higher affinity for WB4101 and phentolamine respectively, than the α_(1b) -receptor and was partially inactivated (65%) by CEC.

Molecular cloning and pharmacological studies have demonstrated the existence of at least three α₁ -adrenergic receptor subtypes. However, it is not clear whether the pharmacological properties of these three cognates might be due also to species differences. This caveat is particularly relevant in the case of the bovine α_(1c) receptor, due to its restricted species and tissue expression. The cloning and expression of the human α₁ adrenergic receptors will allow the further characterization of the pharmacology of the individual human α₁ receptor subtypes.

SUMMARY OF THE INVENTION

This invention provides and isolated nucleic acid molecule encoding a human α₁ adrenergic receptor. This invention further provides an isolated nucleic acid molecule encoding a human α_(1a) receptor. In one embodiment of this invention, the nucleic acid molecule comprises a plasmid pcEXV-α_(1a). This invention also provides an isolated nucleic acid molecule encoding a human α_(1b) receptor. In one embodiment of this invention, the nucleic acid molecule comprises a plasmid pcEXV-α_(1b). This invention further provides an isolated nucleic acid molecule encoding a human α_(1c) receptor. In one embodiment of this invention, the nucleic acid molecule comprises a plasmid pcEXV-α_(1c).

This invention also provides vectors such as plasmids comprising a DNA molecule encoding a human α_(1a) receptor, adapted for expression in a bacterial, a yeast cell, or a mammalian cell which additionally comprise regulatory elements necessary for expression of the DNA in the bacteria, yeast or mammalian cells so located relative to the DNA encoding the human α_(1a) receptor as to permit expression thereof. This invention also provides vectors such as plasmids comprising a DNA molecule encoding a human α_(1b) receptor, adapted for expression in a bacterial, a yeast cell, or a mammalian cell which additionally comprise regulatory elements necessary for expression of the DNA in the bacteria, yeast or mammalian cells so located relative to the DNA encoding the human receptor as to permit expression thereof. This invention also provides vectors such as plasmids comprising a DNA molecule encoding a human α_(1c) receptor, adapted for expression in a bacterial, a yeast cell, or a mammalian cell which additionally comprise regulatory elements necessary for expression of the DNA in the bacteria, yeast or mammalian cells so located relative to the DNA encoding the human α_(1c) receptor as to permit expression thereof.

This invention provides a mammalian cell comprising a DNA molecule encoding a human α_(1a) receptor. This invention also provides a mammalian cell comprising a DNA molecule encoding a human α_(1b) receptor. This invention also provides a mammalian cell comprising a DNA molecule encoding a human α_(1c) receptor.

This invention provides a nucleic acid probe comprising a nucleic acid molecule of at least 15 nucleotides capable of specifically hybridizing with a sequence included within the sequence of a nucleic acid molecule encoding a human α_(1a) receptor. This invention provides a nucleic acid probe comprising a nucleic acid molecule of at least 15 nucleotides capable of specifically hybridizing with a sequence included within the sequence of a nucleic acid molecule encoding a human α_(1b) receptor. This invention provides a nucleic acid probe comprising a nucleic acid molecule of at least 15 nucleotides capable of specifically hybridizing with a sequence included within the sequence of a nucleic acid molecule encoding a human α_(1c) receptor.

This invention provides an antisense oligonucleotide having a sequence capable of specifically binding to any sequences of an mRNA molecule encoding a human α_(1a) receptor so as to prevent translation of the mRNA molecule. This invention provides an antisense oligonucleotide having a sequence capable of specifically binding to any sequences of an mRNA molecule encoding a human α_(1b) receptor so as to prevent translation of the mRNA molecule. This invention provides an antisense oligonucleotide having a sequence capable of specifically binding to any sequences of an mRNA molecule encoding a human α_(1c) receptor so as to prevent translation of the mRNA molecule.

This invention provides method for detecting expression of a specific human α₁ adrenergic receptor, which comprises obtaining RNA from cells or tissue, contacting the RNA so obtained with a nucleic acid probe comprising a nucleic acid molecule of at least 15 nucleotides capable of specifically hybridizing with a sequence included within the sequence of a nucleic acid molecule encoding a human α₁ receptor under hybridizing conditions, detecting the presence of any mRNA hybridized to the probe, the presence of mRNA hybridized to the probe indicating expression of the specific human α₁ adrenergic receptor, and thereby detecting the expression of the specific human α₁ adrenergic receptor.

This invention provides a method for detecting the expression of a specific human α1 adrenergic receptor in a cell or tissue by in situ hybridization which comprises, contacting the cell or tissue with a nucleic acid probe comprising a nucleic acid molecule of at least 15 nucleotides capable of specifically hybridizing with a sequence included within the sequence of a nucleic acid molecule encoding a human α₁ receptor under hybridizing conditions, detecting the presence of any mRNA hybridized to the probe, the presence of mRNA hybridized to the probe indicating expression of the specific human α₁ adrenergic receptor, and thereby detecting the expression of the specific human α₁ adrenergic receptor.

This invention provides a method for isolating a nucleic acid molecule encoding a receptor by nucleic acid sequence homology using a nucleic acid probe, the sequence of which is derived from the nucleic acid sequence encoding a human α1 adrenergic receptor.

This invention provides a method for isolating a nucleic acid molecule encoding a human α₁ adrenergic receptor which comprises the use of the polymerase chain reaction and oligonucleotide primers, the sequence of which are derived from the nucleic acid sequence encoding a human α1 adrenergic receptor.

This invention provides a method for isolating a human α₁ adrenergic receptor protein which comprises inducing cells to express the human α₁ adrenergic receptor protein, recovering the human α₁ adrenergic receptor from the resulting cells, and purifying the human α₁ adrenergic receptor so recovered.

This invention provides an antibody to the human α_(1a) adrenergic receptor. This invention also provides an antibody to the human α_(1b) adrenergic receptor. This invention also provides an antibody to the human α_(1c) adrenergic receptor.

A pharmaceutical composition comprising an amount of a substance effective to alleviate the abnormalities resulting from overexpression of a human α_(1a) adrenergic receptor and a pharmaceutically acceptable carrier is provided by this invention. A pharmaceutical composition comprising an amount of a substance effective to alleviate the abnormalities resulting from overexpression of a human α_(1b) adrenergic receptor and a pharmaceutically acceptable carrier is provided by this invention. A pharmaceutical composition comprising an amount of a substance effective to alleviate the abnormalities resulting from overexpression of a human α_(1c) adrenergic receptor and a pharmaceutically acceptable carrier is provided by this invention.

A pharmaceutical composition comprising an amount of a substance effective to alleviate abnormalities resulting from underexpression of a human α_(1a) adrenergic receptor and a pharmaceutically acceptable carrier is provided by this invention. A pharmaceutical composition comprising an amount of a substance effective to alleviate abnormalities resulting from underexpression of a human α_(1b) adrenergic receptor and a pharmaceutically acceptable carrier is provided by this invention. A pharmaceutical composition comprising an amount of a substance effective to alleviate abnormalities resulting from underexpression of a human α_(1c) adrenergic receptor and a pharmaceutically acceptable carrier is provided by this invention.

This invention provides a transgenic non-human mammal whose genome comprises a nucleic acid molecule encoding a human α1 adrenergic receptor, the DNA molecule so placed as to be transcribed into antisense mRNA complementary to mRNA encoding a human α₁ adrenergic receptor and which hybridizes to mRNA encoding a human α₁ adrenergic receptor thereby reducing its translation.

This invention provides a method for determining the physiological effects of varying the levels of expression of a specific human α1 adrenergic receptor which comprises producing a transgenic non-human mammal whose levels of expression of a human α₁ adrenergic receptor can be varied by use of an inducible promoter.

This invention provides method for determining the physiological effects of expressing varying levels of a specific human α₁ adrenergic receptor which comprises producing a panel of transgenic non-human mammals each expressing a different amount of the human α₁ adrenergic receptor.

This invention provides a method for determining whether a ligand not known to be capable of specifically binding to a human α₁ adrenergic receptor can bind to a human α₁ adrenergic receptor, which comprises contacting a mammalian cell comprising a plasmid adapted for expression in a mammalian cell which further comprises a DNA molecule which expresses a human α₁ adrenergic receptor on the cell surface with the ligand under conditions permitting binding of ligands known to bind to a human α₁ adrenergic receptor, detecting the presence of any ligand bound to the human α₁ adrenergic receptor, the presence of bound ligand thereby determining the ligand binds to the human α₁ adrenergic receptor.

This invention provides a method for screening drugs to identify drugs which interact with, and specifically bind to, a human α₁ adrenergic receptor on the surface of a cell, which comprises contacting a mammalian cell which comprises a plasmid adapted for expression in a mammalian cell which further comprises a DNA molecule which expresses a human α₁ adrenergic receptor on the cell surface with a plurality of drugs, determining those drugs which bind to the human α₁ adrenergic receptor expressed on the cell surface of the mammalian cell, and thereby identifying drugs which interact with, and bind to, the human α₁ adrenergic receptor.

This invention provides a method for identifying a ligand which binds to and activates or blocks the activation of, a human α₁ adrenergic receptor expressed on the surface of a cell, which comprises contacting a mammalian cell which comprises a plasmid adapted for expression in a mammalian cell which further comprises a DNA molecule which expresses a human α₁ adrenergic receptor on the cell surface with the ligand, determining whether the ligand binds to and activates or blocks the activation of the receptor using a bioassay such as a second messenger assays.

This invention also provides a method for identifying a ligand which is capable of binding to and activating or inhibiting a human α₁ adrenergic receptor, which comprises contacting a mammalian cell, wherein the membrane lipids have been labelled by prior incubation with a labelled lipid precursor molecule, the mammalian cell comprising a plasmid adapted for expression in a mammalian cell which further comprises a DNA molecule which expresses a human α₁ adrenergic receptor with the ligand and identifying an inositol phosphate metabolite released from the membrane lipid as a result of ligand binding to and activating an α₁ adrenergic receptor.

This invention also provides a method for identifying a ligand that is capable of binding to and activating or inhibiting a human α₁ adrenergic receptor, wherein the binding of ligand to the adrenergic receptor results in a physiological response, which comprises contacting a mammalian cell which comprises a plasmid adapted for expression in a mammalian cell which further comprises a DNA molecule which expresses a human α₁ adrenergic receptor with a calcium sensitive fluorescent indicator, removing the indicator that has not been taken up by the cell, contacting the cells with the ligand and identifying an increase or decrease in intracellular Ca⁺² as a result of ligand binding to and activating and inhibiting α₁ adrenergic receptor activity receptor.

This invention provides a method for detecting the presence of a human α_(1a) adrenergic receptor on the surface of a cell, which comprises contacting the cell with an antibody to human α_(1a) adrenergic receptor under conditions which permit binding of the antibody to the receptor, detecting the presence of any of the antibody bound to the human α1a adrenergic receptor and thereby the presence of a human α_(1a) adrenergic receptor on the surface of the cell.

This invention provides a method for detecting the presence of a human α_(1b) adrenergic receptor on the surface of a cell, which comprises contacting the cell with an antibody to human α_(1b) adrenergic receptor under conditions which permit binding of the antibody to the receptor, detecting the presence of any of the antibody bound to the human α_(1b) adrenergic receptor and thereby the presence of a human α_(1b) adrenergic receptor on the surface of the cell.

This invention provides a method for detecting the presence of a human α_(1c) adrenergic receptor on the surface of a cell, which comprises contacting the cell with an antibody to human α_(1c) adrenergic receptor under conditions which permit binding of the antibody to the receptor, detecting the presence of any of the antibody bound to the human α_(1c) adrenergic receptor and thereby the presence of a human α_(1c) adrenergic receptor on the surface of the cell.

This invention provides a method of treating an abnormal condition related to an excess of activity of a human α₁ adrenergic receptor subtype, which comprises administering an amount of a pharmaceutical composition effective to reduce α₁ adrenergic activity as a result of naturally occurring substrate binding to and activating a specific α₁ adrenergic receptor.

This invention provides a method for treating abnormalities which are alleviated by an increase in the activity of a specific human α₁ adrenergic receptor, which comprises administering a patient an amount of a pharmaceutical composition effective to increase the activity of the specific human α₁ adrenergic receptor thereby alleviating abnormalities resulting from abnormally low receptor activity.

This invention provides a method for diagnosing a disorder or a predisposition to a disorder associated with the expression of a specific human α₁ adrenergic receptor allele which comprises: a.) obtaining DNA from subjects suffering from a disorder; b.) performing a restriction digest of the DNA with a panel of restriction enzymes; c.) electrophoretically separating the resulting DNA fragments on a sizing gel; d.) contacting the gel with a nucleic acid probe labelled with a detectable marker and which hybridizes to the nucleic acid encoding a specific human α₁ adrenergic receptor; e.) detecting the labelled bands which have hybridized to the DNA encoding the specific α₁ adrenergic receptor labelled with the detectable marker to create a unique band pattern specific to the DNA of subjects suffering with the disorder; f.) preparing DNA for diagnosis by steps a-e; g.)comparing the unique band pattern specific to the DNA of patients suffering from the disorder from step e and DNA obtained for diagnosis from step f to determine whether the patterns are the same or different and to diagnose-thereby predisposition to the disorder if the patterns are the same.

This invention provides a method for identifying a substance capable of alleviating the abnormalities resulting from overexpression of a specific human α₁ adrenergic receptor which comprises administering a substance to the transgenic non-human mammal comprising the DNA encoding a specific α₁ adrenergic receptor and determining whether the substance alleviates the physical and behavioral abnormalities displayed by the transgenic nonhuman mammal as a result of overexpression of the human α₁ adrenergic receptor subtype.

This invention provides a method for identifying a substance capable of alleviating the abnormalities resulting from underexpression of a human α₁ adrenergic receptor subtype, which comprises administering a substance to a non-human transgenic mammal which is expressing a human α₁ adrenergic receptor incapable of receptor activity or is underexpressing the human α₁ adrenergic receptor subtype, and determining whether the substance alleviates the physical and behavioral abnormalities displayed by the transgenic nonhuman mammal as a result of underexpression of a human α₁ adrenergic receptor subtype.

This invention provides a method of treating abnormalities in a subject, wherein the abnormality is alleviated by the reduced expression of a human α₁ adrenergic receptor subtype which comprises administering to a subject an effective amount of the pharmaceutical composition effective to reduce expression of a specific α₁ adrenergic receptor subtype.

This invention provides a method of treating abnormalities resulting from underexpression of a human α₁ adrenergic receptor which comprises administering to a subject an amount of a pharmaceutical composition effective to alleviate abnormalities resulting from underexpression of the specific human α₁ adrenergic receptor.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1, which comprises FIGS. 1A-1I Nucleotide Sequence and Deduced Amino Acid Sequence of Novel Human Alpha-1a Adrenergic Receptor. Nucleotides are presented in the 5' to 3' orientation and the coding region is numbered starting from the initiating methionine and ending in the termination codon. Deduced amino acid sequence by translation of a long open reading frame is shown, along with the 5' and 3' untranslated regions. Numbers in the left and right margins represent nucleotide (top line) and amino acid (bottom line) numberings, starting with the first position as the adenosine (A) and the initiating methionine (M), respectively.

FIG. 2, which comprises FIGS. 2A-2H Nucleotide Sequence and Deduced Amino Acid Sequence of Novel Human Alpha-1b Adrenergic Receptor. Nucleotides are presented in the 5' to 3' orientation and the coding region is numbered starting from the initiating methionine and ending in the termination codon. Deduced amino acid sequence by translation of a long open reading frame is shown, along with the 5' and 3' untranslated regions. Numbers in the left and right margins represent nucleotide (top line) and amino acid (bottom line) numberings, starting with the first position as the adenosine (A) and the initiating methionine (M), respectively.

FIG. 3, which comprises FIGS. 3A-3G Nucleotide Sequence and Deduced Amino Acid Sequence of Novel Human Alpha-1c Adrenergic Receptor. Nucleotides are presented in the 5' to 3' orientation and the coding region is numbered starting from the initiating methionine and ending in the termination codon. Deduced amino acid sequence by translation of a long open reading frame is shown, along with the 5' and 3' untranslated regions. Numbers in the left and right margins represent nucleotide (top line) and amino acid (bottom line) numberings, starting with the first position as the adenosine (A) and the initiating methionine (M), respectively.

FIG. 4, which comprises FIGS. 4A-4D Alignment of the Human Alpha-1a, H318/3 Alpha-1a, and Rat Alpha-1a Adrenergic Receptors. The deduced amino acid sequence of the human α_(1a) receptor (first line), from the starting methionine (M) to the stop codon (*), is aligned with the previously published human "α_(1a) " adrenergic receptor clone, H318/3 (2)(second line) and with the rat alpha-1a (12)(third line). Also shown is a consensus amino acid sequence (fourth line), containing a hyphen at a particular position, when all receptors have the same amino acid or an amino acid at this position, when there is disparity in the three receptors. Dots indicate spaces corresponding to no amino acid at this position. Note that the human and rat α_(1a) receptors have greater homology in the amino (positions 1-90) and carboxyl (positions 440-598) termini than do the previously published "α_(1a) " (H318/3) and rat α_(1a) receptors (see text). Dots indicate spaces corresponding to no amino acid at this position. Numbers above amino acid sequences correspond to amino acid positions, starting with the initiating methionine (M) and ending with the termination codon (*).

FIG. 5, which comprises FIGS. 5A-5D Alignment of the Human Alpha-1b, Hamster Alpha-1b, and Rat Alpha-1b Adrenergic Receptors. The deduced amino acid sequence of the human α_(1b) receptor (third line), from the starting methionine (M) to the stop codon (*), is aligned with the previously published rat α_(1b) adrenergic receptor clone (25)(first line) and with the hamster alpha-1b (4)(second line). Also shown is a consensus amino acid sequence (fourth line), containing a hyphen at a particular position, when all receptors have the same amino acid or an amino acid at this position, when there is disparity in the three receptors. Dots indicate spaces corresponding to no amino acid at this position. Numbers above amino acid sequences correspond to amino acid position, starting with the initiating methionine (M) and ending with the termination codon (*).

FIG. 6, which comprises FIGS. 6A-6C Alignment of the Human Alpha-1c and Bovine Alpha-1c Adrenergic Receptors. The deduced amino acid sequence of the human α_(1c) receptor (first line), from the starting methionine (M) to the stop codon (*), is aligned with the previously published bovine α_(1b) adrenergic receptor clone (13)(first line). Also shown is a consensus amino acid sequence (third line), containing a hyphen at a particular position, when all receptors have the same amino acid or an amino acid at this position, when there is disparity in the three receptors. Dots indicate spaces corresponding to no amino acid at this position. Numbers above amino acid sequences correspond to amino acid position, starting with the initiating methionine (M) and ending with the termination codon (*).

DETAILED DESCRIPTION OF THE INVENTION

This invention provides an isolated nucleic acid molecule encoding a human α₁ adrenergic receptor. This invention also provides an isolated nucleic acid molecule encoding a human α_(1a) adrenergic receptor. This invention also provides an isolated nucleic acid molecule encoding a human α_(1b) adrenergic receptor. This invention also provides an isolated nucleic acid molecule encoding a human α_(1c) adrenergic receptor. As used herein, the term "isolated nucleic acid molecule" means a non-naturally occurring nucleic acid molecule that is, a molecule in a form which does not occur in nature. Examples of such an isolated nucleic acid molecule are an RNA, cDNA, or an isolated genomic DNA molecule encoding a human α_(1a), human α_(1b) or human α_(1c) adrenergic receptor. As used herein, the term "α_(1a) receptor", "α_(1b) receptor", or "α_(1c) receptor" means a molecule which is a distinct member of a class of α₁ adrenergic receptor molecules which under physiologic conditions, is substantially specific for the the catecholamines epinephrine and norepinephrine, is saturable, and having high affinity for the catecholamines epinephrine and norepinephrine. The term "α₁ adrenergic receptor subtype" refers to a distinct member of the class of human α₁ adrenergic receptors, which may be any one of the human α_(1a), α_(1b) or α_(1c) adrenergic receptors. The term "specific α₁ adrenergic receptor" refers to a distinct member of the group or class of human α₁ adrenergic receptors, which may be any one of the human α_(1a), α_(1b) or α_(1c) adrenergic receptors. One embodiment of this invention is an isolated human nucleic acid molecule encoding a human α_(1a) adrenergic receptor. Such a molecule may have coding sequences substantially the same as the coding sequence in FIGS. 1A-1I. The DNA molecule of FIGS. 1A-1I encodes the sequence of the human α_(1a) adrenergic receptor. Another, preferred embodiment is an isolated human nucleic acid molecule encoding a human α_(1b) adrenergic receptor. Such a molecule may have coding sequences substantially the same as the coding sequence in FIGS. 2A-2H. The DNA molecule of FIGS. 2A-2H encodes the sequence of the human α_(1b) adrenergic receptor. Another, preferred embodiment is an isolated human nucleic acid molecule encoding a human α_(1c) adrenergic receptor. Such a molecule may have coding sequences substantially the same as the coding sequence in FIGS. 3A-3G. The DNA molecule of FIGS. 3A-3G encodes the sequence of the human α_(1c) adrenergic receptor. One means of isolating a nucleic acid molecule encoding a α₁ adrenergic receptor is to screen a genomic DNA or cDNA library with a natural or artificially designed DNA probe, using methods well known in the art. In the preferred embodiment of this invention, α₁ adrenergic receptors include the human α_(1a), human α_(1b) and human α_(1c) adrenergic receptors and the nucleic acid molecules encoding them were isolated by screening a human genomic DNA library and by further screening screening of a human cDNA library to obtain the sequence of the entire human α_(1a), human α_(1b) or human α_(1c) adrenergic receptor. To obtain a single nucleic acid molecule encoding the entire human α_(1a), α_(1b) or α_(1c) adrenergic receptor two or more DNA clones encoding portions of the same receptor were digested with DNA restriction endonuleases and ligated together with DNA ligase in the proper orientation using techniques known to one of skill in the art. DNA or cDNA molecules which encode a human α_(1a), α_(1b) or α_(1c) adrenergic receptor are used to obtain complementary genomic DNA, cDNA or RNA from human, mammalian or other animal sources, or to isolate related cDNA or genomic DNA clones by the screening of cDNA or genomic DNA libraries, by methods described in more detail below. Transcriptional regulatory elements from the 5' untranslated region of the isolated clone, and other stability, processing, transcription, translation, and tissue specificity determining regions from the 3' and 5' untranslated regions of the isolated gene are thereby obtained.

This invention provides an isolated nucleic acid molecule which has been so mutated as to be incapable of encoding a molecule having normal human α₁ adrenergic receptor activity, and not expressing native human α₁ adrenergic receptor. An example of a mutated nucleic acid molecule provided by this invention is an isolated nucleic acid molecule which has an in-frame stop codon inserted into the coding sequence such that the transcribed RNA is not translated into protein.

This invention provides a cDNA molecule encoding a human α_(1a) adrenergic receptor, wherein the cDNA molecule has a coding sequence substantially the same as the coding sequence shown in FIGS. 1A-1I. This invention also provides a cDNA molecule encoding a human α_(1b) adrenergic receptor, wherein the cDNA molecule has a coding sequence substantially the same as the coding sequence shown in FIGS. 2A-2H. This invention also provides a cDNA molecule encoding a human α_(1c) adrenergic receptor, wherein the cDNA molecule has a coding sequence substantially the same as the coding sequence shown in FIGS. 3A-3G. These molecules and their equivalents were obtained by the means further described below.

This invention provides an isolated protein which is a human α₁ adrenergic receptor. In one embodiment of this invention, the protein is a human α_(1a) adrenergic receptor having an amino acid sequence substantially similar to the amino acid sequence shown in FIGS. 1A-IH. In another embodiment of this invention, the protein is a human α_(1b) adrenergic receptor having an amino acid sequence substantially similar to the amino acid sequence shown in FIGS. 2A-2H. In another embodiment of this invention, the protein is a human α_(1c) adrenergic receptor having an amino acid sequence substantially similar to the amino acid sequence shown in FIGS. 3A-3G. As used herein, the term "isolated protein" is intended to encompass a protein molecule free of other cellular components. One means for obtaining an isolated human α₁ adrenergic receptor is to express DNA encoding the α₁ adrenergic receptor in a suitable host, such as a bacterial, yeast, or mammalian cell, using methods well known to those skilled in the art, and recovering the human α₁ adrenergic receptor after it has been expressed in such a host, again using methods well known in the art. The human α₁ adrenergic receptor may also be isolated from cells which express it, in particular from cells which have been transfected with the expression vectors described below in more detail.

This invention also provides a vector comprising an isolated nucleic acid molecule such as DNA, RNA, or cDNA, encoding a human α_(1a) receptor. This invention also provides a vector comprising an isolated nucleic acid molecule such as DNA, RNA, or cDNA, encoding a human human α_(1b) adrenergic receptor. This invention also provides a vector comprising an isolated nucleic acid molecule such as DNA, RNA, or cDNA, encoding a human human α_(1c) adrenergic receptor. Examples of vectors are viruses such as bacteriophages (such as phage lambda), cosmids, plasmids (such as pUC18, available from Pharmacia, Piscataway, N.J.), and other recombination vectors. Nucleic acid molecules are inserted into vector genomes by methods well known to those skilled in the art. Examples of such plasmids are plasmids comprising cDNA having a coding sequence substantially the same as: the coding sequence shown in FIGS. 1A-1I, 2A-2H, and FIGS. 3A-3G. Alternatively, to obtain these vectors, insert and vector DNA can both be exposed to a restriction enzyme to create complementary ends on both molecules which base pair with each other and are then ligated together with a ligase. Alternatively, linkers can be ligated to the insert DNA which correspond to a restriction site in the vector DNA, which is then digested with the restriction enzyme which cuts at that site. Other means are also available.

This invention also provides vectors comprising a DNA molecule encoding a human α_(1a), vectors comprising a DNA molecule encoding a human α_(1b) adrenergic receptor and vectors comprising a DNA molecule encoding a human α_(1c) adrenergic receptor adapted for expression in a bacterial cell, a yeast cell, or a mammalian cell which additionally comprise the regulatory elements necessary for expression of the DNA in the bacterial, yeast, or mammalian cells so located relative to the DNA encoding a human α₁ adrenergic receptor as to permit expression thereof. DNA having coding sequences substantially the same as the coding sequence shown in FIGS. 1A-1I may be inserted into the vectors to express a human α_(1a) adrenergic receptor. DNA having coding sequences substantially the same as the coding sequence shown in FIGS. 2A-2H may be inserted into the vectors to express a human α_(1b) adrenergic receptor. DNA having coding sequences substantially the same as the coding sequence shown in FIGS. 3A-3G may usefully be inserted into the vectors to express a human α_(1c) adrenergic receptor. Regulatory elements required for expression include promoter sequences to bind RNA polymerase and transcription initiation sequences for ribosome binding. For example, a bacterial expression vector includes a promoter such as the lac promoter and for transcription initiation the Shine-Dalgarno sequence and the start codon AUG (Maniatis, et al., Molecular Cloning, Cold Spring Harbor Laboratory, 1982). Similarly, a eukaryotic expression vector includes a heterologous or homologous promoter for RNA polymerase II, a downstream polyadenylation signal, the start codon AUG, and a termination codon for detachment of the ribosome. Such vectors may be obtained commercially or assembled from the sequences described by methods well known in the art, for example the methods described above for constructing vectors in general. Expression vectors are useful to produce cells that express a human α₁ adrenergic receptor. Certain uses for such cells are described in more detail below.

In one embodiment of this invention a plasmid is adapted for expression in a bacterial, yeast, or, in particular, a mammalian cell wherein the plasmid comprises a DNA molecule encoding a human α_(1a) adrenergic receptor, a DNA molecule encoding a human α_(1b) adrenergic receptor or a DNA molecule encoding a human α_(1c) adrenergic receptor and the regulatory elements necessary for expression of the DNA in the bacterial, yeast, or mammalian cell so located relative to the DNA encoding a human α₁ adrenergic receptor as to permit expression thereof. Suitable plasmids may include, but are not limited to plasmids adapted for expression in a mammalian cell, e.g., pCEXV-3 derived expression vector. Examples of such plasmids adapted for expression in a mammalian cell are plasmids comprising cDNA having coding sequences substantially the same as the coding sequence shown in FIGS. 1A-1I, 2A-2H, and 3A-3G and the regulatory elements necessary for expression of the DNA in the mammalian cell. These plasmids have been designated pcEXV-α_(1a) deposited under ATCC Accession No., pcEXV-α_(1b) deposited under ATCC Accession No., and pcEXV-α_(1c) deposited under ATCC Accession No., respectively . Those skilled in the art will readily appreciate that numerous plasmids adapted for expression in a mammalian cell which comprise DNA encoding human α₁ adrenergic receptors and the regulatory elements necessary to express such DNA in the mammalian cell may be constructed utilizing existing plasmids and adapted as appropriate to contain the regulatory elements necessary to express the DNA in the mammalian cell. The plasmids may be constructed by the methods described above for expression vectors and vectors in general, and by other methods well known in the art.

The deposits discussed supra were made pursuant to, and in satisfaction of, the provisions of the Budapest Treaty on the International Recognition of the Deposit of Microorganisms for the Purpose of Patent Procedure with the American Type Culture Collection (ATCC), 12301 Parklawn Drive, Rockville, Md. 20852.

This invention provides a mammalian cell comprising a DNA molecule encoding a human α₁ adrenergic receptor, such as a mammalian cell comprising a plasmid adapted for expression in a mammalian cell, which comprises a DNA molecule encoding a human α₁ adrenergic receptor and the regulatory elements necessary for expression of the DNA in the mammalian cell so located relative to the DNA encoding a human α₁ adrenergic receptor as to permit expression thereof. Numerous mammalian cells may be used as hosts, including, but not limited to, the mouse fibroblast cell NIH3T3, CHO cells, HeLa cells, Ltk-cells, human embryonic kidney cells, Cos cells, etc.

Expression plasmids such as that described supra may be used to transfect mammalian cells by methods well known in the art such as calcium phosphate precipitation, or DNA encoding these human α₁ adrenergic receptors may be otherwise introduced into mammalian cells, e.g., by microinjection, to obtain mammalian cells which comprise DNA, e.g., cDNA or a plasmid, encoding a human α₁ adrenergic receptor.

This invention provides a nucleic acid probe comprising a nucleic acid molecule of at least 15 nucleotides capable of specifically hybridizing with a sequence included within the sequence of a nucleic acid molecule encoding a human α_(1a) adrenergic receptor, for example with a coding sequence included within the sequence shown in FIGS. 1A-1I. This invention also provides a nucleic acid probe comprising a nucleic acid molecule of at least 15 nucleotides capable of specifically hybridizing with a sequence included within the sequence of a nucleic acid molecule encoding a human α_(1b) adrenergic receptor, for example with a coding sequence included within the sequence shown in FIGS. 2A-2H. This invention also provides a nucleic acid probe comprising a nucleic acid molecule of at least 15 nucleotides capable of specifically hybridizing with a sequence included within the sequence of a nucleic acid molecule encoding a human α_(1c) adrenergic receptor, for example with a coding sequence included within the sequence shown in FIGS. 3A-3G. As used herein, the phrase "specifically hybridizing" means the ability of a nucleic acid molecule to recognize a nucleic acid sequence complementary to its own and to form double-helical segments through hydrogen bonding between complementary base pairs. Nucleic acid probe technology is well known to those skilled in the art who will readily appreciate that such probes may vary greatly in length and may be labeled with a detectable label, such as a radioisotope or fluorescent dye, to facilitate detection of the probe. Detection of nucleic acid encoding a human α₁ adrenergic receptor is useful as a diagnostic test for any disease process in which levels of expression of the corresponding human α_(1a), α_(1b) or α_(1c) adrenergic receptor are altered. DNA probe molecules are produced by insertion of a DNA molecule which encodes a human α_(1a), human α_(1b), or human α_(1c) adrenergic receptor or fragments thereof into suitable vectors, such as plasmids or bacteriophages, followed by insertion into suitable bacterial host cells and replication and harvesting of the DNA probes, all using methods well known in the art. For example, the DNA may be extracted from a cell lysate using phenol and ethanol, digested with restriction enzymes corresponding to the insertion sites of the DNA into the vector (discussed above), electrophoresed, and cut out of the resulting gel. Examples of such DNA molecules are shown in FIGS. 1A-1I, 2A-2H, and 3A-3G. The probes are useful for `in situ` hybridization or in order to identify tissues which express this gene family, or for other hybridization assays for the presence of these genes or their mRNA in various biological tissues. In addition, synthesized oligonucleotides (produced by a DNA synthesizer) complementary to the sequence of a DNA molecule which encodes a human α_(1a) adrenergic receptor, or complementary to the sequence of a DNA molecule which encodes a human α_(1b) adrenergic receptor or complementary to the sequence of a DNA molecule which encodes a human α_(1c) adrenergic receptor are useful as probes for these genes, for their associated mRNA, or for the isolation of related genes by homology screening of genomic or cDNA libraries, or by the use of amplification techniques such as the Polymerase Chain Reaction.

This invention also provides a method for detecting expression of a human α_(1a) adrenergic receptor on the surface of a cell by detecting the presence of mRNA coding for a human α_(1a) adrenergic receptor. This invention also provides a method for detecting expression of a human α_(1b) adrenergic receptor on the surface of a cell by detecting the presence of mRNA coding for a human α_(1b) adrenergic receptor. This invention also provides a method for detecting expression of a human α_(1c) adrenergic receptor on the surface of a cell by detecting the presence of mRNA coding for a human α_(1c) adrenergic receptor. These methods comprise obtaining total mRNA from the cell using methods well known in the art and contacting the mRNA so obtained with a nucleic acid probe as described hereinabove, under hybridizing conditions, detecting the presence of mRNA hybridized to the probe, and thereby detecting the expression of the human α₁ adrenergic receptor by the cell. Hybridization of probes to target nucleic acid molecules such as mRNA molecules employs techniques well known in the art. However, in one embodiment of this invention, nucleic acids are extracted by precipitation from lysed cells and the mRNA is isolated from the extract using a column which binds the poly-A tails of the mRNA molecules (Maniatis, T. et al., Molecular Cloning; Cold Spring Harbor Laboratory, pp.197-98 (1982)). The mRNA is then exposed to radioactively labelled probe on a nitrocellulose membrane, and the probe hybridizes to and thereby labels complementary mRNA sequences. Binding may be detected by autoradiography or scintillation counting. However, other methods for performing these steps are well known to those skilled in the art, and the discussion above is merely an example.

This invention provides an antisense oligonucleotide having a sequence capable of specifically binding with any sequences of an mRNA molecule which encodes a human α_(1a) adrenergic receptor so as to prevent translation of the human α_(1a) adrenergic receptor. This invention also provides an antisense oligonucleotide having a sequence capable of specifically binding with any sequences of an mRNA molecule which encodes a human α_(1b) adrenergic receptor so as to prevent translation of the human α_(1b) adrenergic receptor. This invention also provides an antisense oligonucleotide having a sequence capable of binding specifically with any sequences of an mRNA molecule which encodes a human α_(1c) adrenergic receptor so as to prevent translation of the human α_(1c) adrenergic receptor. As used herein, the phrase "specifically binding" means the ability of an antisense oligonucleotide to recognize a nucleic acid sequence complementary to its own and to form double-helical segments through hydrogen bonding between complementary base pairs. The antisense oligonucleotide may have a sequence capable of specifically binding with any sequences of the cDNA molecules whose sequences are shown in FIGS. 1A-1I, 2A-2H or 3A-3G. A particular example of an antisense oligonucleotide is an antisense oligonucleotide comprising chemical analogues of nucleotides which are known to one of skill in the art.

This invention also provides a pharmaceutical composition comprising an effective amount of the oligonucleotide described above effective to reduce expression of a human α_(1a) adrenergic receptor, by passing through a cell membrane and specifically binding with mRNA encoding the human α_(1a) adrenergic receptor in the cell so as to prevent its translation and a pharmaceutically acceptable hydrophobic carrier capable of passing through a cell membrane. This invention also provides a pharmaceutical composition comprising an effective amount of the oligonucleotide described above effective to reduce expression of a human α_(1b) adrenergic receptor, by passing through a cell membrane and specifically binding with mRNA encoding the the human α_(1b) adrenergic receptor in the cell so as to prevent its translation and a pharmaceutically acceptable hydrophobic carrier capable of passing through a cell membrane. This invention further provides a pharmaceutical composition comprising an effective amount of the oligonucleotide described above effective to reduce expression of a human α_(1c) adrenergic receptor, by passing through a cell membrane and specifically binding with mRNA encoding the human α_(1c) adrenergic receptor in the cell so as to prevent its translation and a pharmaceutically acceptable hydrophobic carrier capable of passing through a cell membrane. As used herein, the term "pharmaceutically acceptable carrier" encompasses any of the standard pharmaceutical carriers, such as a phosphate buffered saline solution, water, and emulsions, such as an oil/water or water/oil emulsion, and various types of wetting agents. The oligonucleotide may be coupled to a substance which inactivates mRNA, such as a ribozyme. The pharmaceutically acceptable hydrophobic carrier capable of passing through cell membranes may also comprise a structure which binds to a transporter specific for a selected cell type and is thereby taken up by cells of the selected cell type. The structure may be part of a protein known to bind a cell-type specific transporter, for example an insulin molecule, which would target pancreatic cells. DNA molecules having coding sequences substantially the same as the coding sequence shown in FIGS. 1A-1I, 2A-2H, or 3A-3G may be used as the oligonucleotides of the pharmaceutical composition.

This invention also provides a method of treating abnormalities which are alleviated by reduction of expression of a human α₁ adrenergic receptor. This method comprises administering to a subject an effective amount of the pharmaceutical composition described above effective to reduce expression of the human α1 adrenergic receptor by the subject. This invention further provides a method of treating an abnormal condition related to α₁ adrenergic receptor activity which comprises administering to a subject an amount of the pharmaceutical composition described above effective to reduce expression of the human α₁ adrenergic receptor by the subject. An example of such an abnormal condition is benign prostatic hypertrophy.

Antisense oligonucleotide drugs inhibit translation of mRNA encoding the human α_(1a), human α_(1b) or human α_(1c) adrenergic receptors. Synthetic antisense oligonucleotides, or other antisense chemical structures are designed to bind to mRNA encoding the human α_(1a) adrenergic receptor, to mRNA encoding the human α_(1b) adrenergic receptor or to mRNA encoding the human α_(1c) adrenergic receptor and inhibit translation of mRNA and are useful as drugs to inhibit expression of the human α_(1a) adrenergic receptor the human α_(1b) adrenergic receptor or the human α_(1c) adrenergic receptor in patients. This invention provides a means to therapeutically alter levels of expression of the human α_(1a) adrenergic receptor, the human α_(1b) adrenergic receptor or the human α_(1c) adrenergic receptor by the use of a synthetic antisense oligonucleotide drug (SAOD) which inhibits translation of mRNA encoding these α₁ adrenergic receptors. Synthetic antisense oligonucleotides, or other antisense chemical structures designed to recognize and selectively bind to mRNA, are constructed to be complementary to portions of the nucleotide sequences shown in FIGS. 1A-1I, 2A-2H, or 3A-3G of DNA, RNA or of chemically modified, artificial nucleic acids. The SAOD is designed to be stable in the blood stream for administration to patients by injection, or in laboratory cell culture conditions, for administration to cells removed from the patient. The SAOD is designed to be capable of passing through cell membranes in order to enter the cytoplasm of the cell by virtue of physical and chemical properties of the SAOD which render it capable of passing through cell membranes (e.g., by designing small, hydrophobic SAOD chemical structures) or by virtue of specific transport systems in the cell which recognize and transport the SAOD into the cell. In addition, the SAOD can be designed for administration only to certain selected cell populations by targeting the SAOD to be recognized by specific cellular uptake mechanisms which bind and take up the SAOD only within certain selected cell populations. For example, the SAOD may be designed to bind to a transporter found only in a certain cell type, as discussed above. The SAOD is also designed to recognize and selectively bind to the target mRNA sequence, which may correspond to a sequence contained within the sequences shown in FIGS. 1A-1I, 2A-2H, or 3A-3G by virtue of complementary base pairing to the mRNA. Finally, the SAOD is designed to inactivate the target mRNA sequence by any of three mechanisms: 1) by binding to the target mRNA and thus inducing degradation of the mRNA by intrinsic cellular mechanisms such as RNAse I digestion, 2) by inhibiting translation of the mRNA target by interfering with the binding of translation-regulating factors or of ribosomes, or 3) by inclusion of other chemical structures, such as ribozyme sequences or reactive chemical groups, which either degrade or chemically modify the target mRNA. Synthetic antisense oligonucleotide drugs have been shown to be capable of the properties described above when directed against mRNA targets (J. S. Cohen, Trends in Pharm. Sci. 10, 435 (1989); H. M. Weintraub, Sci. Am. January (1990) p. 40). In addition, coupling of ribozymes to antisense oligonucleotides is a promising strategy for inactivating target mRNA (N. Sarver et al., Science 247, 1222 (1990)). An SAOD serves as an effective therapeutic agent if it is designed to be administered to a patient by injection, or if the patient's target cells are removed, treated with the SAOD in the laboratory, and replaced in the patient. In this manner, an SAOD serves as a therapy to reduce human α₁ adrenergic receptor expression in particular target cells of a patient, in any clinical condition which may benefit from reduced expression of a specific human α₁ adrenergic receptor.

This invention provides an antibody directed to a human α_(1a) adrenergic receptor. This antibody may comprise, for example, a monoclonal antibody directed to an epitope of a human α_(1a) adrenergic receptor present on the surface of a cell, the epitope having an amino acid sequence substantially the same as an amino acid sequence for a cell surface epitope of the human α_(1a) adrenergic receptor included in the amino acid sequence shown in FIGS. 1A-1I. This invention also provides an antibody directed to a human α_(1b) adrenergic receptor. This antibody may comprise, for example, a monoclonal antibody directed to an epitope of a human α_(1b) adrenergic receptor present on the surface of a cell, the epitope having an amino acid sequence substantially the same as an amino acid sequence for a cell surface epitope of the human α_(1b) adrenergic receptor included in the amino acid sequence shown in FIGS. 2A-2H. This invention also provides an antibody directed to a human α_(1c) adrenergic receptor. This antibody may comprise, for example, a monoclonal antibody directed to an epitope of a human α_(1c) adrenergic receptor present on the surface of a cell, the epitope having an amino acid sequence substantially the same as an amino acid sequence for a cell surface epitope of the human α_(1c) adrenergic receptor included in the amino acid sequence shown in FIGS. 3A-3G. Amino acid sequences may be analyzed by methods well known to those skilled in the art to determine whether they produce hydrophobic or hydrophilic regions in the proteins which they build. In the case of cell membrane proteins, hydrophobic regions are well known to form the part of the protein that is inserted into the lipid bilayer which forms the cell membrane, while hydrophilic regions are located on the cell surface, in an aqueous environment. Therefore antibodies to the hydrophilic amino acid sequences shown in FIGS. 1A-1I will bind to a surface epitope of a the human α_(1a) adrenergic receptor, antibodies to the hydrophilic amino acid sequences shown in FIGS. 2A-2H will bind to a surface epitope of a human α_(1b) adrenergic receptor, and antibodies to the hydrophilic amino acid sequences shown in FIGS. 3A-3G will bind to a surface epitope of a human α_(1c) adrenergic receptor as described. Antibodies directed to human α₁ adrenergic receptors may be serum-derived or monoclonal and are prepared using methods well known in the art. For example, monoclonal antibodies are prepared using hybridoma technology by fusing antibody producing B cells from immunized animals with myeloma cells and selecting the resulting hybridoma cell line producing the desired antibody. Cells such as NIH3T3 cells or Ltk- cells may be used as immunogens to raise such an antibody. Alternatively, synthetic peptides may be prepared using commercially available machines and the amino acid sequences shown in FIGS. 1A-1I, 2A-2H, and 3A-3G. As a still further alternative, DNA, such as a cDNA or a fragment thereof, may be cloned and expressed and the resulting polypeptide recovered and used as an immunogen. These antibodies are useful to detect the presence of human α₁ adrenergic receptors encoded by the isolated DNA, or to inhibit the function of α₁ adrenergic receptors in living animals, in humans, or in biological tissues or fluids isolated from animals or humans.

This invention provides a pharmaceutical composition which comprises an effective amount of an antibody directed to an epitope of a human α_(1a) adrenergic receptor, effective to block binding of naturally occurring substrates to the human α_(1a) adrenergic receptor and a pharmaceutically acceptable carrier. A monoclonal antibody directed to an epitope of a human α_(1a) adrenergic receptor present on the surface of a cell which has an amino acid sequence substantially the same as an amino acid sequence for a cell surface epitope of the human α_(1a) adrenergic receptor included in the amino acid sequence shown in FIGS. 1A-1I is useful for this purpose. This invention also provides a pharmaceutical composition which comprises an effective amount of an antibody directed to an epitope of a human α_(1b) adrenergic receptor, effective to block binding of naturally occurring substrates to the human α_(1b) adrenergic receptor and a pharmaceutically acceptable carrier. A monoclonal antibody directed to an epitope of a human α_(1b) adrenergic receptor present on the surface of a cell which has an amino acid sequence substantially the same as an amino acid sequence for a cell surface epitope of the human α_(1b) adrenergic receptor included in the amino acid sequence shown in FIGS. 2A-2H is useful for this purpose. This invention provides a pharmaceutical composition which comprises an effective amount of an antibody directed to an epitope of a human α_(1c) adrenergic receptor, effective to block binding of naturally occurring substrates to the human α_(1c) adrenergic receptor and a pharmaceutically acceptable carrier. A monoclonal antibody directed to an epitope of a human α_(1c) adrenergic receptor present on the surface of a cell which has an amino acid sequence substantially the same as an amino acid sequence for a cell surface epitope of the human α_(1c) adrenergic receptor included in the amino acid sequence shown in FIGS. 3A-3G is useful for this purpose.

This invention also provides a method of treating abnormalities in a subject which are alleviated by reduction of expression of a specific human α₁ adrenergic receptor. The method comprises administering to the subject an effective amount of the pharmaceutical composition described above effective to block binding of naturally occurring substrates to the human α₁ adrenergic receptor and thereby alleviate abnormalities resulting from overexpression of the human α₁ adrenergic receptor. Binding of the antibody to the human α₁ adrenergic receptor prevents the human α₁ adrenergic receptor from functioning, thereby neutralizing the effects of overexpression. The monoclonal antibodies described above are useful for this purpose. This invention additionally provides a method of treating an abnormal condition related to an excess of a specific human α₁ adrenergic receptor activity which comprises administering to a subject an amount of the pharmaceutical composition described above effective to block binding of naturally occurring substrates to the human α1 adrenergic receptor and thereby alleviate the abnormal condition. An example of an abnormal condition associated with excess human α1 adrenergic receptor activity is benign prostatic hypertrophy.

This invention provides methods of detecting the presence of a specific human α1 adrenergic receptor on the surface of a cell which comprises contacting the cell with an antibody directed to a specific human α1 adrenergic receptor, under conditions permitting binding of the antibody to the human α1 adrenergic receptor, detecting the presence of any antibody bound to the α1 adrenergic receptor, and thereby the presence of the specific human α1 adrenergic receptor on the surface of the cell. Such methods are useful for determining whether a given cell is defective in expression of a specific human α1 adrenergic receptor. Bound antibodies are detected by methods well known in the art, for example by binding fluorescent markers to the antibodies and examining the cell sample under a fluorescence microscope to detect fluorescence on a cell indicative of antibody binding. The monoclonal antibodies described above are useful for this purpose.

This invention provides a transgenic nonhuman mammal comprising DNA encoding a human α_(1a) adrenergic receptor. This invention also provides a transgenic nonhuman mammal comprising DNA encoding a human α_(1b) adrenergic receptor. This invention also provides a transgenic nonhuman mammal comprising DNA encoding a human α_(1c) adrenergic receptor.

This invention also provides a transgenic nonhuman mammal comprising DNA encoding a human α_(1a) adrenergic receptor so mutated as to be incapable of normal human α_(1a) adrenergic receptor activity, and not expressing native human α1a adrenergic receptor. This invention also provides a transgenic nonhuman mammal comprising DNA encoding a human α_(1b) adrenergic receptor so mutated as to be incapable of normal human α1b adrenergic receptor activity, and not expressing native human α1b adrenergic receptor. This invention also provides a transgenic nonhuman mammal comprising DNA encoding a human α_(1c) adrenergic receptor so mutated as to be incapable of normal human α1c adrenergic receptor activity, and not expressing native human α_(1c) adrenergic receptor.

This invention provides a transgenic non-human animal whose genome comprises DNA encoding a human α_(1a) adrenergic receptor so placed as to be transcribed into antisense mRNA which is complementary to mRNA encoding a human α_(1a) adrenergic receptor and which hybridizes to mRNA encoding the human α_(1a) adrenergic receptor thereby reducing its translation. This invention also provides a transgenic nonhuman mammal whose genome comprises DNA encoding a human α_(1b) adrenergic receptor so placed as to be transcribed into antisense mRNA which is complementary to mRNA encoding the human α_(1b) adrenergic receptor and which hybridizes to mRNA encoding a human α_(1b) adrenergic receptor thereby reducing its translation. This invention provides a transgenic non-human animal whose genome comprises DNA encoding a human α_(1c) adrenergic receptor so placed as to be transcribed into antisense mRNA which is complementary to mRNA encoding a human α_(1c) adrenergic receptor and which hybridizes to mRNA encoding the human α_(1c) adrenergic receptor thereby reducing its translation. The DNA may additionally comprise an inducible promoter or additionally comprise tissue specific regulatory elements, so that expression can be induced, or restricted to specific cell types. Examples of DNA are DNA or cDNA molecules having a coding sequence substantially the same as the coding sequences shown in FIGS. 1A-1I, 2A-2H, or 3A-3G. An example of a transgenic animal is a transgenic mouse. Examples of tissue specificity-determining regions are the metallothionein promotor (Low, M. J., Lechan, R. M., Hammer, R. E. et al. Science 231:1002-1004 (1986)) and the L7 promotor (Oberdick, J., Smeyne, R. J., Mann, J. R., Jackson, S. and Morgan, J. I. Science 248:223-226 (1990)).

Animal model systems which elucidate the physiological and behavioral roles of human α₁ adrenergic receptors are produced by creating transgenic animals in which the expression of an α₁ adrenergic receptor is either increased or decreased, or the amino acid sequence of the expressed α₁ adrenergic receptor is altered, by a variety of techniques. Examples of these techniques include, but are not limited to: 1) Insertion of normal or mutant versions of DNA encoding a human α₁ adrenergic receptor or homologous animal versions of these genes, by microinjection, retroviral infection or other means well known to those skilled in the art, into appropriate fertilized embryos in order to produce a transgenic animal (Hogan B. et al. Manipulating the Mouse Embryo, A Laboratory Manual, Cold Spring Harbor Laboratory (1986)) or, 2) Homologous recombination (Capecchi M. R. Science 244:1288-1292 (1989); Zimmer, A. and Gruss, P. Nature 338:150-153 (1989)) of mutant or normal, human or animal version of the genes encoding α1 adrenergic receptors with the native gene locus in transgenic animals to alter the regulation of expression or the structure α1 of these α₁ adrenergic receptors. The technique of homologous recombination is well known in the art. It replaces the native gene with the inserted gene and so is useful for producing an animal that cannot express native α₁ adrenergic receptor but does express, for example, an inserted mutant human α₁ adrenergic receptor, which has replaced the native α₁ adrenergic receptor in the animal's genome by recombination, resulting in underexpression of the α₁ adrenergic receptor. Microinjection adds genes to the genome, but does not remove them, and so is useful for producing an animal which expresses its own and added α₁ adrenergic receptors, resulting in overexpression of the α₁ adrenergic receptor.

One means available for producing a transgenic animal, with a mouse as an example, is as follows: Female mice are mated, and the resulting fertilized eggs are dissected out of their oviducts. The eggs are stored in an appropriate medium such as M2 medium (Hogan B. et al. Manipulating the Mouse Embryo, A Laboratory Manual, Cold Spring Harbor Laboratory (1986)). DNA or cDNA encoding a human α₁ adrenergic receptor is purified from a vector (such as plasmids pCEXV-α_(1a), pCEXV-α_(1b), or pCEXV-α_(1c) described above) by methods well known in the art. Inducible promoters may be fused with the coding region of the DNA to provide an experimental means to regulate expression of the trans-gene. Alternatively or in addition, tissue specific regulatory elements may be fused with the coding region to permit tissue-specific expression of the trans-gene. The DNA, in an appropriately buffered solution, is put into a microinjection needle (which may be made from capillary tubing using a pipet puller) and the egg to be injected is put in a depression slide. The needle is inserted into the pronucleus of the egg, and the DNA solution is injected. The injected egg is then transferred into the oviduct of a pseudopregnant mouse (a mouse stimulated by the appropriate hormones to maintain pregnancy but which is not actually pregnant), where it proceeds to the uterus, implants, and develops to term. As noted above, microinjection is not the only method for inserting DNA into the egg cell, and is used here only for exemplary purposes. Since the normal action of α₁ adrenergic-specific drugs is to activate or to inhibit the α₁ adrenergic receptor, the transgenic animal model systems described above are useful for testing the biological activity of drugs directed against specific human α₁ adrenergic receptors even before such drugs become available. These animal model systems are useful for predicting or evaluating possible therapeutic applications of drugs which activate or inhibit these human α₁ adrenergic receptors by inducing or inhibiting expression of the native or transgene and thus increasing or decreasing expression of normal or mutant human α₁ adrenergic receptor in the living animal. Thus, a model system is produced in which the biological activity of drugs directed against these human α₁ adrenergic receptors are evaluated before such drugs become available. The transgenic animals which over or under produce a specific human α₁ adrenergic receptor indicate by their physiological state whether over or under production of the human α₁ adrenergic receptor is therapeutically useful. It is therefore useful to evaluate drug action based on the transgenic model system. One use is based on the fact that it is well known in the art that a drug such as an antidepressant acts by blocking neurotransmitter uptake, and thereby increases the amount of neurotransmitter in the synaptic cleft. The physiological result of this action is to stimulate the production of less human α₁ adrenergic receptor by the affected cells, leading eventually to underexpression. Therefore, an animal which underexpresses human α₁ adrenergic receptor is useful as a test system to investigate whether the actions of such drugs which result in under expression are in fact therapeutic. Another use is that if overexpression is found to lead to abnormalities, then a drug which down-regulates or acts as an antagonist to the human α₁ adrenergic receptor is indicated as worth developing, and if a promising therapeutic application is uncovered by these animal model systems, activation or inhibition of the specific human α₁ adrenergic receptor is achieved therapeutically either by producing agonist or antagonist drugs directed against these human α₁ adrenergic receptors or by any method which increases or decreases the expression of these α₁ adrenergic receptors in man.

Further provided by this invention is a method of determining the physiological effects of expressing varying levels of a human α₁ adrenergic receptor which comprises producing a transgenic nonhuman animal whose levels of α₁ adrenergic receptor expression are varied by use of an inducible promoter which regulates human α₁ adrenergic receptor expression. This invention also provides a method of determining the physiological effects of expressing varying levels of human α₁ adrenergic receptors which comprises producing a panel of transgenic nonhuman animals each expressing a different amount of a human α₁ adrenergic receptor. Such animals may be produced by introducing different amounts of DNA encoding a human α₁ adrenergic receptor into the oocytes from which the transgenic animals are developed.

This invention also provides a method for identifying a substance capable of alleviating abnormalities resulting from overexpression of a human α₁ adrenergic receptor comprising administering the substance to a transgenic nonhuman mammal expressing at least one artificially introduced DNA molecule encoding a human α₁ adrenergic receptor and determining whether the substance alleviates the physical and behavioral abnormalities displayed by the transgenic nonhuman mammal as a result of overexpression of a human α₁ adrenergic receptor. As used herein, the term "substance" means a compound or composition which may be natural, synthetic, or a product derived from screening. Examples of DNA molecules are DNA or cDNA molecules having a coding sequence substantially the same as the coding sequences shown in FIGS. 1A-1I, 2A-2H, or 3A-3G.

This invention provides a pharmaceutical composition comprising an amount of the substance described supra effective to alleviate the abnormalities resulting from overexpression of a human α_(1a) adrenergic receptor and a pharmaceutically acceptable carrier. This invention provides a pharmaceutical composition comprising an amount of the substance described supra effective to alleviate the abnormalities resulting from overexpression of a human α_(1b) adrenergic receptor and a pharmaceutically acceptable carrier. This invention also provides a pharmaceutical composition comprising an amount of the substance described supra effective to alleviate the abnormalities resulting from overexpression of a human α_(1c) adrenergic receptor and a pharmaceutically acceptable carrier.

This invention further provides a method for treating the abnormalities resulting from overexpression of a human α₁ adrenergic receptor which comprises administering to a subject an amount of the pharmaceutical composition described above effective to alleviate the abnormalities resulting from overexpression of the human α₁ adrenergic receptor.

This invention provides a method for identifying a substance capable of alleviating the abnormalities resulting from underexpression of a human α₁ adrenergic receptor comprising administering the substance to the transgenic nonhuman mammal described above which expresses only a nonfunctional human α₁ adrenergic receptor and determining whether the substance alleviates the physical and behavioral abnormalities displayed by the transgenic nonhuman mammal as a result of underexpression of the human α₁ adrenergic receptor.

This invention also provides a pharmaceutical composition comprising an amount of a substance effective to alleviate abnormalities resulting from underexpression of a human α₁ adrenergic receptor and a pharmaceutically acceptable carrier.

This invention further provides a method for treating the abnormalities resulting from underexpression of a human α₁ adrenergic receptor which comprises administering to a subject an amount of the pharmaceutical composition described above effective to alleviate the abnormalities resulting from underexpression of a human α₁ adrenergic receptor.

This invention provides a method for diagnosing a predisposition to a disorder associated with the expression of a specific human α₁ adrenergic receptor allele which comprises: a) obtaining DNA of subjects suffering from the disorder; b) performing a restriction digest of the DNA with a panel of restriction enzymes; c) electrophoretically separating the resulting DNA fragments on a sizing gel; d) contacting the resulting gel with a nucleic acid probe capable of specifically hybridizing to DNA encoding a human α₁ adrenergic receptor and labelled with a detectable marker; e) detecting labelled bands which have hybridized to the DNA encoding a human α₁ adrenergic receptor labelled with a detectable marker to create a unique band pattern specific to the DNA of subjects suffering from the disorder; f) preparing DNA obtained for diagnosis by steps a-e; and g) comparing the unique band pattern specific to the DNA of subjects suffering from the disorder from step e and the DNA obtained for diagnosis from step f to determine whether the patterns are the same or different and thereby to diagnose predisposition to the disorder if the patterns are the same. This method may also be used to diagnose a disorder associated with the expression of a specific human α₁ adrenergic receptor allele.

This invention provides a method of preparing an isolated human α₁ adrenergic receptor which comprises inducing cells to express the human α₁ adrenergic receptor, recovering the α₁ adrenergic receptor from the resulting cells, and purifying the α₁ adrenergic receptor so recovered. An example of an isolated human α_(1a) adrenergic receptor is an isolated protein having substantially the same amino acid sequence as the amino acid sequence shown in FIGS. 1A-1I. An example of an isolated human α_(1b) adrenergic receptor is an isolated protein having substantially the same amino acid sequence shown in FIG. 2A-2H. An example of an isolated human α_(1c) adrenergic receptor is an isolated protein having substantially the same amino acid sequence shown in FIG. 3A-3G. For example, cells can be induced to express human α₁ adrenergic receptors by exposure to substances such as hormones. The cells can then be homogenized and the human α₁ adrenergic receptor isolated from the homogenate using an affinity column comprising, for example, epinephrine, norepinephrine, or another substance which is known to bind to the human α₁ adrenergic receptor. The resulting fractions can then be purified by contacting them with an ion exchange column, and determining which fraction contains human α₁ adrenergic receptor activity or binds anti-human α1 adrenergic receptor antibodies.

This invention provides a method of preparing the isolated human α_(1a) adrenergic receptor which comprises inserting nucleic acid encoding the human α_(1a) adrenergic receptor in a suitable vector, inserting the resulting vector in a suitable host cell, recovering the α_(1a) adrenergic receptor produced by the resulting cell, and purifying the α_(1a) adrenergic receptor so recovered. An example of an isolated human α_(1a) adrenergic receptor is an isolated protein having substantially the same amino acid sequence as the amino acid sequence shown in FIGS. 1A-1I. This invention also provides a method of preparing the isolated human α_(1b) adrenergic receptor which comprises inserting nucleic acid encoding the human α_(1b) adrenergic receptor in a suitable vector, inserting the resulting vector in a suitable host cell, recovering the α_(1b) adrenergic receptor produced by the resulting cell, and purifying the α_(1b) adrenergic receptor so recovered. This invention also provides a method of preparing the isolated human α_(1c) adrenergic receptor which comprises inserting nucleic acid encoding the human α_(1c) adrenergic receptor in a suitable vector, inserting the resulting vector in a suitable host cell, recovering the α_(1c) adrenergic receptor produced by the resulting cell, and purifying the α_(1c) adrenergic receptor so recovered. These methods for preparing human α₁ adrenergic receptors uses recombinant DNA technology methods well known in the art. For example, isolated nucleic acid encoding a human α1 adrenergic receptor is inserted in a suitable vector, such as an expression vector. A suitable host cell, such as a bacterial cell, or a eukaryotic cell such as a yeast cell, is transfected with the vector. The human α₁ adrenergic receptor is isolated from the culture medium by affinity purification or by chromatography or by other methods well known in the art.

This invention provides a method of determining whether a ligand not known to be capable of binding to a human α₁ adrenergic receptor can bind to a human α₁ adrenergic receptor, which comprises contacting a mammalian cell comprising a plasmid adapted for expression in a mammalian cell which further comprises a DNA molecule which expresses a human α₁ adrenergic receptor on the cell surface with the ligand under conditions permitting binding of ligands known to bind to the human α₁ adrenergic receptor, detecting the presence of any ligand bound to the human α₁ adrenergic receptor and thereby determining whether the ligand binds to the human α₁ adrenergic receptor. The DNA in the cell may have a coding sequence substantially the same as the coding sequences shown in FIGS. 1A-1I, 2A-2H, or 3A-3G, preferably, the mammalian cell is nonneuronal in origin. An example of a nonneuronal mammalian cell is a Cos7 cell. The preferred method for determining whether a ligand is capable of binding to the human α₁ adrenergic receptor comprises contacting a transfected nonneuronal mammalian cell (i.e. a cell that does not naturally express any type of human α₁ adrenergic receptor, thus will only express such human α₁ adrenergic receptor if it is transfected into the cell) expressing a human α₁ adrenergic receptor on its surface, or contacting a membrane preparation derived from such a transfected cell, with the ligand under conditions which are known to to prevail, and thus to be associated with in vivo binding of the substrates to a human α1 adrenergic receptor, detecting the presence of any of the ligand being tested bound to the human α₁ adrenergic receptor on the surface of the cell, and thereby determining whether the ligand binds to the human α₁ adrenergic receptor. This response system is obtained by transfection of isolated DNA into a suitable host cell. Such a host system might be isolated from pre-existing cell lines, or can be generated by inserting appropriate components into existing cell lines. Such a transfection system provides a complete response system for investigation or assay of the functional activity of human α₁ adrenergic receptors with ligands as described above. Transfection systems are useful as living cell cultures for competitive binding assays between known or candidate drugs and substrates which bind to the human α₁ adrenergic receptor and which are labeled by radioactive, spectroscopic or other reagents. Membrane preparations containing the transporter isolated from transfected cells are also useful for these competitive binding assays. A transfection system constitutes a "drug discovery system" useful for the identification of natural or synthetic compounds with potential for drug development that can be further modified or used directly as therapeutic compounds to activate or inhibit the natural functions of a specific human α₁ adrenergic receptor. The transfection system is also useful for determining the affinity and efficacy of known drugs at human α₁ adrenergic receptor binding sites.

This invention provides a method for identifying a ligand which interacts with, and activates or blocks the activation of, a human α₁ adrenergic receptor on the surface of a cell, which comprises contacting a mammalian cell which comprises a plasmid adapted for expression in a mammalian cell which further comprises a DNA molecule which expresses a human α₁ adrenergic receptor on the cell surface with the ligand, determining whether the ligand activates or blocks the activation of the receptor using a bioassay such as second messenger assays, and thereby identifying a ligand which interacts with, and activates or blocks the activation of, a human α₁ adrenergic receptor.

This invention provides functional assays for identifying ligands and drugs which bind to and activate or inhibit a specific human el adrenergic receptor activity.

This invention provides a method for identifying a ligand which is capable of binding to and activating or inhibiting a human α₁ adrenergic receptor, which comprises contacting a mammalian cell, wherein the membrane lipids have been labelled by prior incubation with a labelled lipid precursor molecule, the mammalian cell comprising a plasmid adapted for expression in a mammalian cell which further comprises a DNA molecule which expresses a human α₁ adrenergic receptor with the ligand and identifying an inositol phosphate metabolite released from the membrane lipid as a result of ligand binding to and activating an α₁ adrenergic receptor.

This invention provides method for identifying a ligand that is capable of binding to and activating or inhibiting a human α₁ adrenergic receptor, wherein the binding of ligand to the adrenergic receptor results in a physiological response, which comprises contacting a mammalian cell which comprises a plasmid adapted for expression in a mammalian cell which further comprises a DNA molecule which expresses a human α₁ adrenergic receptor with a calcium sensitive fluorescent indicator, removing the indicator that has not been taken up by the cell, contacting the cells with the ligand and identifying an increase or decrease in intracellular Ca⁺² as a result of ligand binding to and activating receptor.

Transformed mammalian cells for idenmtifying the ligands and drugs that affect the functional properties of the human α adrenergic receptors include 293-α1-10, C-α1b-6 and C-α1c-7.

This invention also provides a method of screening drugs to identify drugs which interact with, and bind to, a human α₁ adrenergic receptor on the surface of a cell, which comprises contacting a mammalian cell which comprises a plasmid adapted for expression in a mammalian cell which further comprises a DNA molecule which expresses a human α₁ adrenergic receptor on the cell surface with a plurality of drugs, determining those drugs which bind to the human α₁ adrenergic receptor expressed on the cell surface of the mammalian cell, and thereby identifying drugs which interact with, and bind to, the human α₁ adrenergic receptor. Various methods of detection may be employed. The drugs may be "labeled" by association with a detectable marker substance (e.g., radiolabel or a non-isotopic label such as biotin). The DNA in the cell may have a coding sequence substantially the same as the coding sequences shown in FIGS. 1A-1I, 2A-2H or 3A-3G. Preferably, the mammalian cell is nonneuronal in origin. An example of a nonneuronal mammalian cell is a Cos7 cell. Drug candidates are identified by choosing chemical compounds which bind with high affinity to the human α₁ adrenergic receptor expressed on the cell surface in transfected cells, using radioligand binding methods well known in the art, examples of which are shown in the binding assays described herein. Drug candidates are also screened for selectivity by identifying compounds which bind with high affinity to one particular human α₁ adrenergic receptor subtype but do not bind with high affinity to any other human α₁ adrenergic receptor subtype or to any other known receptor site. Because selective, high affinity compounds interact primarily with the target human α₁ adrenergic site after administration to the patient, the chances of producing a drug with unwanted side effects are minimized by this approach. This invention provides a pharmaceutical composition comprising a drug identified by the method described above and a pharmaceutically acceptable carrier. As used herein, the term "pharmaceutically acceptable carrier" encompasses any of the standard pharmaceutical carriers, such as a phosphate buffered saline solution, water, and emulsions, such as an oil/water or water/oil emulsion, and various types of wetting agents. Once the candidate drug has been shown to be adequately bio-available following a particular route of administration, for example orally or by injection (adequate therapeutic concentrations must be maintained at the site of action for an adequate period to gain the desired therapeutic benefit), and has been shown to be non-toxic and therapeutically effective in appropriate disease models, the drug may be administered to patients by that route of administration determined to make the drug bio-available, in an appropriate solid or solution formulation, to gain the desired therapeutic benefit.

Applicants have identified individual human α₁ adrenergic receptor subtypes and have described methods for the identification of pharmacological compounds for therapeutic treatments. Pharmacological compounds which are directed against a specific human α₁ adrenergic receptor subtype provide effective new therapies with minimal side effects.

Elucidation of the molecular structures of the neuronal human α₁ adrenergic receptors transporters is an important step in the understanding of α-adrenergic neurotransmission. This disclosure reports the isolation, the nucleic acid sequence, and functional expression of DNA clones isolated from human brain which encode human α₁ adrenergic receptors. The identification of these human α₁ adrenergic receptors will play a pivotal role in elucidating the molecular mechanisms underlying α-adrenergic transmission, and should also aid in the development of novel therapeutic agents.

DNA clones encoding human α₁ adrenergic receptors have been isolated from human brain, and their functional properties have been examined in mammalian cells.

This invention identifies for the first time three new human α₁ adrenergic receptors, their amino acid sequences, and their human genes. The information and experimental tools provided by this discovery are useful to generate new therapeutic agents, and new therapeutic or diagnostic assays for these new human receptors, their associated mRNA molecules or their associated genomic DNAs. The information and experimental tools provided by this discovery will be useful to generate new therapeutic agents, and new therapeutic or diagnostic assays for these new human receptors, their associated mRNA molecules, or their associated genomic DNAs.

Specifically, this invention relates to the first isolation of human DNA clones encoding encoding three α₁ -adrenergic receptors. In addition, the human α₁ adrenergic receptors have been expressed in mammalian cells by transfecting the cells with the plasmids pCEXV-α_(1a), pCEXV-α_(1b), and pCEXV-α_(1c). The pharmacological binding properties of these receptor proteins have been determined, and these binding properties classify these receptor proteins as α₁ adrenergic receptors. Mammalian cell lines expressing the human α₁ adrenergic receptors on the cell surface have been constructed, thus establishing the first well-defined, cultured cell lines with which to study human α₁ adrenergic receptors. Examples of transformed mammalian cells, expressing human α₁ adrenergic receptors are L-α1a, expressing a human α1a adrenergic receptor, L-α1b expressing a human α1b adrenergic receptor, and L-α1c expressing a human α1c adrenergic receptor. These cells are suitable for studying the pharmacological properties of the human α1 adrenergic receptors and for the screening of ligands and drugs that specifically bind to human α1 adrenergic receptor subtypes.

The invention will be better understood by reference to the Experimental Details which follow, but those skilled in the art will readily appreciate that the specific experiments detailed are only illustrative, and are not meant to limit the invention as described herein, which is defined by the claims which follow thereafter.

MATERIALS AND METHODS Cloning and Sequencing

α1a: A human lymphocyte genomic library in λ dash II (≈1.5×10⁶ total recombinants; Stratagene, LaJolla, Calif.) was screened using a cloned rat PCR fragment (RBNC2) as a probe. RBNC2 was obtained by amplifying randomly-primed rat brain cDNA with degenerate primers designed to conserved regions of transmembrane (Tm) regions 3 and 6 of serotonin receptors. The sequence of one PCR product, RBNC2, exhibited strong homology to the α1 AR family.

The probe was labeled with [³² P] by the method of random priming (5) (Prime-It Random Primer kit, Stratagene, LaJolla, Calif.). Hybridization was performed at 40° C. in a solution containing 50% formamide, 10% dextran sulfate, 5× SSC (1× SSC is 0.15M sodium chloride, 0.015M sodium citrate), 1× Denhardt's solution (0.02% polyvinylpyrrolidone, 0.02% Ficoll, 0.02% bovine serum albumin), and 200 μg/μl sonicated salmon sperm DNA. The filters were washed at 50° C. in 0.1× SSC containing 0.1% sodium dodecyl sulfate and exposed at -70° C. to Kodak XAR film in the presence of an intensifying screen. Lambda phage clones hybridizing with the probe were plaque purified and DNA was prepared for Southern blot analysis (22, 17). For subcloning and further Southern blot analysis, DNA was cloned into pUC18 (Pharmacia, Piscataway, N.J.) or pBluescript (Stratagene, LaJolla, Calif.). Nucleotide sequence analysis was accomplished by the Sanger dideoxy nucleotide chain termination method (18) on denatured double-stranded plasmid templates, using Sequenase (US Biochemical Corp., Cleveland, Ohio), Bst DNA sequencing kit (Bio-Rad Laboratories, Richmond, Calif.), or TaqTrack sequencing kit (Promega Corporation, Madison, Wis.).

In order to isolate a full-length clone, human cDNA libraries were screened by polymerase chain reaction (PCR) with 1 μM each of specific oligonucleotide primers designed off the isolated genomic clone: from the sense strand (nucleotide 598-626), 5' CACTCAAGTACCCAGCCATCATGAC 3' and from the anti-sense strand (nucleotide 979-1003), 5' CGGAGAGCGAGCTGCGGAAGGTGTG 3' (see FIGS. 1A-1I). The primers were from non-conserved portions of the receptor gene, specifically in the Tm3-Tm4 loop and in the Tm5-Tm6 loop regions for the upstream and downstream primers, respectively. One to 2 μl of phage DNA from cDNA libraries (λ ZapII; Stratagene, LaJolla, Calif.), representing ≈10⁶ -10⁷ pfu, were amplified in 10 mM Tris-HCl, pH 8.3, 50 mM KCl, 1.5 mM MgCl2, 0.01% gelatin, 200 μM each dATP, dCTP, dGTP, dTTP, 2.5 units of Thermus aquaticus DNA polymerase (Taq polymerase; Perkin-Elmer-Cetus, Norwalk, Conn.). The amplification profile was run for 30 cycles: a 5 min. initial (ie. 1 cycle) denaturation at 95° C., followed by 2 min. at 94° C., 2 min. at 68° C., and 3 min. at 72° C., with a 3 sec. extension, followed by a final 10 min. extension at 72° C. PCR products were analyzed by ethidium bromide (EtBr) stained agarose gels and any sample exhibiting a band on the EtBr stained gel was considered positive.

A positive library was then plated and screened with overlapping 45-mer oligonucleotide probes, filled-in using [α-³² P]dCTP and [α-³² P]dATP and Klenow fragment of DNA polymerase. This probe was internal to the amplification primers discussed above: from the sense strand (nucleotide 890-934), 5'GCAAGGCCTCCGAGGTGGTGCTGCGCATCCACTGTCGCGGCGCGG 3', and from the anti-sense strand (nucleotide 915-961), 5' TGCCGTGCGCCCCGTCGGCGCCCGTGGCCGCGCCGCGACAGTGGATG 3' (see FIGS. 1A-1I). Positive cDNA phage clones were plaque purified and pBluescript recombinant DNAs were excision-rescued from λ Zap II using helper phage R408, as described by manufacturer's protocol (Stratagene, LaJolla, Calif.). Insert size was confirmed by restriction enzyme digest analysis and recombinants were sequenced, as described above.

α1b: A human placenta genomic library in λ dash II (≈1.5×10⁶ total recombinants; Stratagene, LaJolla, Calif.) was screened using overlapping 45-mer oligonucleotides radiolabeled as described above and directed to the third, fifth and sixth transmembrane regions of serotonin 5HT1Dβ receptor gene. Hybridization and washing conditions were identical to that described for α1a above except lower stringency hybridization and washes were conducted; specifically, hybridization in 25% formamide and washes at 40° C.

Positive-hybridizing λ phage clones were plaque-purified, analyzed by Southern blot analysis, subcloned and sequenced, as described above for α1a. In order to isolate full-length clones, human cDNA libraries in λ Zap II (Stratagene, LaJolla, Calif.) were screened by polymerase chain reaction as described above. The upstream and downstream PCR primers used were from the Tm4-Tm5 loop and the Tm5-Tm6 loop, respectively: from the sense strand (nucleotide 567-593), 5' CAACGATGACAAGGA GTGCGGGGTCAC 3', and from the antisense strand (nucleotide 822-847), 5' TTTGACAGCTATGGAACTCCTGGGG 3' (see FIG. 2). PCR, library screen, plaque purification excision-rescue from λ Zap II, restriction digestions and sequencing were accomplished as described above for α1a. The internal probe was: from the sense strand (nucleotide 745-789), 5'AAGGAGCTGACCCTGAGGATCCATTCCAAGAACTTTCACGAGGAC 3', and from the anti-sense strand (nucleotide 770-814), 5' CCTTGGCCTTGGTACTGCTAAGGGTGTCCTCGTGAAAGTTCTTGG 3' (see FIGS. 2A-2H).

α1c: A human lymphocyte genomic library in λ dash II (≈1.5×10⁶ total recombinants; Stratagene, LaJolla, Calif.) was screened using overlapping 45-mer oligonucleotides radiolabeled as described for α1a and directed to the third, fifth and sixth transmembrane regions of serotonin 5HT1A receptor gene. Hybridization and washing conditions were identical to that described for α1b. Positive-hybridizing λ phage clones were plaque-purified, analyzed by Southern blot analysis, subcloned and sequenced, as described above for α1a. Identification and isolation of full-length clones by PCR and screening cDNA libraries were accomplished as described for α1b. The upstream and downstream PCR primers used were from the Tm3-Tm4 loop and the Tm5-Tm6 loop, respectively: from the sense strand (nucleotide 403-425), 5' CCAACCATCGTCACCCAGAGGAG 3', and from the antisense strand (nucleotide 775-802), 5' TCTCCCGGGAGAACTTGAGGAGCCTCAC 3' (see FIGS. 3A-3G). The internal probe was: from the sense strand (nucleotide 711-745), 5'TCCGCATCCATCGGAAAAACGCCCCGGCAGGAGGCAGCGGGATGG 3', and from the anti-sense strand (nucleotide 726-771), 5' GAAGTGCGTCTTGGTCTTGGCGCTGGCCATCCCGCTGCCTCCTGCC 3' (see FIGS. 3A-3G). PCR, library screen, plaque purification excision-rescue from λ Zap II, restriction digestions and sequencing were accomplished as described above for α1a.

Expression

α1a: The entire coding region of α1a (1719 bp), including 150 basepairs of 5' untranslated sequence (5' UT) and 300 bp of 3' untranslated sequence (3' UT), was cloned into the BamHI and ClaI sites of the polylinker-modified eukaryotic expression vector pCEXV-3 (13), called EXJ.HR (unpublished data). The construct involved the ligation of partial overlapping human lymphocyte genomic and hippocamppal cDNA clones: 5' sequences were contained on a 1.2 kb SmaI-XhoI genomic fragment (the vector-derived BamHI site was used for subcloning instead of the internal insert-derived SmaI site) and 3' sequences were contained on an 1.3 kb XhoI-ClaI cDNA fragment (the ClaI site was from the vector polylinker). Stable cell lines were obtained by cotransfection with the plasmid α1a/EXJ (expression vector containing the α1a receptor gene) and the plasmid pGCcos3neo (plasmid containing the aminoglycoside transferase gene) into LM(tk⁻), CHO, NIH3T3 cells, and 293 cells using calcium phosphate technique. The cells were grown, in a controlled environment (37° C., 5% CO₂), as monolayers in Dulbecco's modified Eagle's Medium (GIBCO, Grand Island, N.Y.) containing 25 mM glucose and supplemented with 10% bovine calf serum, 100 units/ml penicillin G, and 100 μg/ml streptomycin sulfate. Stable clones were then selected for resistance to the antibiotic G-418 (1 mg/ml) as described previously (26) and membranes were harvested and assayed for their ability to bind [³ H]prazosin as described below (see "Radioligand Binding Assays").

α1b: The entire coding region of α1b (1563 bp), including 200 basepairs of 5' untranslated sequence (5' UT) and 600 bp of 3' untranslated sequence (3' UT), was cloned into the EcoRI site of pCEXV-3 eukaryotic expression vector (5). The construct involved ligating the full-length containing EcoRI brainstem cDNA fragment from λ ZapII into the expression vector. Stable cell lines were selected as described above.

α1c: The entire coding region of α1c (1401 bp) , including 400 basepairs of 5' untranslated sequence (5' UT) and 200 bp of 3' untranslated sequence (3' UT), was cloned into the KpnI site of the polylinker-modified pCEXV-3-derived (13) eukaryotic expression vector, EXJ.RH (unpublished data). The construct involved ligating three partial overlapping fragments: a 5' 0.6 kb HincII genomic clone, a central 1.8 EcoRI hippocamppal cDNA clone, and a 3' 0.6 kb PstI genomic clone. The hippocamppal cDNA fragment overlaps with the 5' and 3' genomic clones so that the HincII and PstI sites at the 5' and 3' ends of the cDNA clone, respectively, were utilized for ligation. This full-length clone was cloned into the KpnI site of the expression vector, using the 5' and 3' KpnI sites of the fragment, derived from vector (ie. pBluescript) and 3' untranslated sequences, respectively. Stable cell lines were selected as described above.

Radioligand Binding Assays

Transfected cells from culture flasks were scraped into 5 ml of 5 mM Tris-HCl, 5 mM EDTA, pH 7.5, and lysed by sonication. The cell lysates were centrifuged at 1000 rpm for 5 min at 4° C., and the supernatant was centrifuged at 30,000×g for 20 min at 4° C. The pellet was suspended in 50 mM Tris-HCl, 1 mM MgCl₂, and 0.1% ascorbic acid at pH 7.5. Binding of the α1 antagonist [³ H]prazosin (0.5 nM, specific activity 76.2 Ci/mmol) to membrane preparations of LM(tk-) cells was done in a final volume of 0.25 ml and incubated at 37° C. for 20 min. Nonspecific binding was determined in the presence of 10 μM phentolamine. The reaction was stopped by filtration through GF/B filters using a cell harvester. Data were analyzed by a computerized non-linear regression program.

Measurement of [³ H]Inositol Phosphates (IP) Formation

Cells were suspended in Dulbecco's phosphate buffered saline (PBS), and incubated with 5μCi/ml [³ H]m-inositol for 60 min at 37° C. The unincorporated radioactivity was removed by low speed centrifugation, and the cells were suspended in PBS containing 10mM LiCl and the reaction was started by adding the agonist. After incubation for 60 min at 37° C., the reaction was stopped by adding CHCl₃ :Methanol:HCl (2/1/0.01 v/v). Total [³ H]IP were separated by ion exchange chromatography and quantified as described by Forray and El-Fakahany (7).

Calcium Measurements

Intracellular calcium levels ([Ca²⁺ ]i) were determined with the calcium-sensitive dye fura-2, and microspectrofluorometry, essentially as previously described (113). Briefly, cells were plated into polylysine-coated coverslip bottom dishes (MatTek Corporation, Ashland Mass.). To load with fura-2, cells were washed 3× with HEPES-buffered saline (HBS, in mM: HEPES, 20; NaCl, 150; KCl, 5; CaCl₂, 1; MgCl₂, 1; glucose, 10; pH 7.4) and incubated for 30 minutes at room temperature with fura-2 loading solution (5uM fura-2/AM, 0.03% pluronic F-127, and 2% heat-inactivated fetal calf serum, in HBS). After loading, cells were washed 3× with HBS, 1 ml of HBS was added, and the dish was placed on the microscope for determination of [Ca²⁺ ]_(i). [Ca²⁺ ]_(i) was measured with a Leitz Fluovert microscope equipped for UV-transmission epifluorescence. Fura-2 fluorescence was alternately excited at 340 and 380 nm (0.25 sec), and a pair of readings (500 nm long pass) was taken every two seconds, and recorded by a personal computer interfaced to a data acquisition and control unit from Kinetek (Yonkers, N.Y.). To determine [Ca²⁺ ]_(i) from the experimental data the background fluorescence was subtracted, and the corrected ratios were converted to [Ca²⁺ ]_(i) by comparison with buffers containing saturating and low free calcium, assuming a K_(D) of 400 nM (3).

RESULTS

α1a: We screened a human genomic lymphocyte library with a rat PCR fragment that exhibited homology with the α1-AR family. A total of six clones were isolated and characterized by Southern blot analysis. One clone, h13, contained a 4.0 kb XbaI fragment which hybridized with the radiolabeled rat PCR fragment and was subsequently subcloned into pUC vector. DNA sequence analysis indicated greatest homology to human α1a and rat α1a ARs. This clone contained the initiating methionine through Tm6 with ≈1.0-1.5 kb 5' UT region. Subsequent Southern blot, analysis, subcloning and sequencing analysis indicated the presence of a SmaI site ≈150 nts. 540 to the initiating methionine codon. The homology between h13 and rat α1a adrenergic gene breaks just downstream of Tm6, indicating an intron which is located in an analogous region in the α1b- and α1c-AR genes (4, 20). In order to obtain a full-length clone, aliquots of human cDNA libraries totaling ≈1.5×10⁶ recombinants was screened by polymerase chain reaction using specific oligonucleotide primers from sequence determined off the genomic clone (see Materials and Methods). A positive-containing human hippocamppal cDNA library (Stratagene, LaJolla, Calif.) in λ ZapII (≈1.5×10⁶ recombinants) was screened using traditional plaque hybridization with an internal probe (see Materials and Methods) and resulted in the isolation of two positive cDNA clones, one containing the upstream sequences (from 5' UT through the 5-6 loop; hH22) and the other containing downstream sequences (from within Tm5 through ≈300 bp 3' UT; hH14). These two clones overlap by ≈200 nts. with a common XhoI site being present within this common region.

The complete full-length gene was constructed by splicing together two restriction fragments, one being the 3' cDNA (hH14) and the other being the 5' genomic clone (h13), using a unique restriction site (XhoI) present in the overlapping region. In addition, another construct was accomplished by ligating the two cDNA clones (hH14 and hH22), using the overlapping XhoI site; however, since this construct produced the same pharmacology as the genomic/cDNA construct, we will not discuss this recombinant (unpublished observation). The genomic/cDNA construct contains an open reading frame of 1719 bp and encoding a protein of 572 aa in length, having a relative molecular mass of ≈63,000 daltons. Hydropathy analysis of the protein is consistent with a putative topography of seven transmembrane domains, indicative of the G protein-coupled receptor family. Initial sequence analysis revealed that clone α1a/EXJ was most related to an AR since it contained a number of conserved structural features/residues found among the members of the adrenergic receptor family, including conserved cysteines in the second and third extracellular loops, a conserved glycine residue in Tm1, aspartic acid residues in Tm regions II and III, conserved valine residues in TmIII, the DRY sequence at the end of TmIII, the conserved proline residues of Tm regions II, IV, V, VI and VII, and the consensus D-V-L-X-X-T-X-S-I-X-X-L-C in Tm3 and the consensus G-Y-X-N-S-X-X-N-P-X-I-Y in Tm VII, both consensus unique to the adrenergic receptor family (2, 26). Other features of this human α1a receptor gene are the presence of two potential sites for N-linked glycosylation in the amino terminus (asparagine residues 65 and 82; FIGS. 1a-1I) and the presence of several serines and threonines in the carboxyl terminus and intracellular loops, which may serve as sites for potential phosphorylation by protein kinases.

α1b: We screened a human genomic placenta library with probes derived from Tm3, 5 and 6 regions of serotonin 5HT1D.sub.β under low stringency. Out of several hundred positive clones pursued by Southern blot analysis, subcloning and sequencing, one resembled the α1 adrenergic family of receptors. This genomic fragment contained Tm3 through Tm6 of a receptor which was most closely related to rat and hamster α1b receptors. In order to obtain a full-length clone, several human cDNA libraries were screened by PCR using primers derived from the 5-6 loop region of the genomic clone (see Materials and Methods). A positive-containing human brainstem cDNA library (Stratagene, LaJolla, Calif.) in λ ZAPII (≈2×10⁶ recombinants) was screened using traditional plaque hybridization with an internal probe, resulting in the isolation of two identical cDNA clones, containing an insert size of 2.4 kb. Upon sequencing, this clone was found to contain the initiating MET aa, Tm1 through Tm7, and 5' and 3' UT sequences, suggesting a full-length clone on a single EcoRI fragment. This cDNA clone contains an open reading frame of 1563 bp and encodes a protein of 520 aa in length, having a relative molecular mass of ≈57,000 daltons. Hydropathy analysis of the protein is consistent with a putative topography of seven transmembrane domains, indicative of the G protein-coupled receptor family.

Sequence analysis revealed that clone α1b/pCEXV was most related to adrenergic receptor since it contained a number of conserved structural features found among the adrenergic receptor family, as described for α1a receptor (see above). This human α1b receptor contains potential sites for N-linked glycosylation in the amino terminus (asparagine residues 10, 24, 29, .34 in FIG. 2A-2H), consistent with the finding that the α1 AR is glycosylated (4, 19).

α1c: We screened a human genomic lymphocyte library with probes derived from the third, fifth and sixth transmembrane regions of serotonin 5HT1A under low stringency. Out of several hundred positive clones analyzed by Southern blot analysis, subcloning and sequencing (see Materials and Methods), one phage clone resembled a novel α1 AR. This genomic fragment contained Tm1 through Tm6 of a receptor with high homology to the bovine α1c receptor and thus suggesting the presence of an intron downstream of Tm6, as shown for the α1 receptor family (4, 12, 20). In order to obtain a full-length clone, several human cDNA libraries were screened by PCR, as described for α1b (also see Materials and Methods). A positive-containing human hippocamppal cDNA library (Stratagene, LaJolla, Calif.) in λ ZAPII (≈2×10⁶ recombinants) was screened, as described for α1b. A positive clone (hH 20) was identified which contained a 1.7 kb EcoRI cDNA fragment insert. However, this cDNA clone lacked both the amino end of the receptor (the 5' end of the clone terminated at the 5' end of Tm2) and part of the carboxyl tail (the 3' end of the clone corresponded to 40 aa upstream from the "putative" stop codon). Since an alternative genomic subclone which contained the initiating MET codon in addition to Tm1 through Tm6 was available, we needed to obtain the complete 3' carboxyl tail in order to complete the construct of the full-length clone. This was accomplished by using overlapping 45-mer oligonucleotide primers (corresponding to nts. 1142-1212 in FIG. 3), designed within the carboxyl tail of the receptor (at the 3' end of the hH20 cDNA clone), to screen a human lymphocyte genomic library in order to isolate a genomic clone containing the carboxyl tail that includes the termination codon. Two identical positive human lymphocyte genomic clones were isolated from this library. A 0.6 kb PstI fragment was subcloned and shown to contain most of the carboxyl tail (≈20 aa downstream of Tm7) through the termination codon and ≈200 bp of 3' UT sequence.

The complete full-length gene was constructed by splicing together three restriction fragments: A 0.6 kb HincII fragment from the genomic clone, containing ≈0.4 kb of 5' UT sequence and the initiating MET codon through Tm2; the 0.8 kb HincII-PstI fragment from the hH cDNA clone, which contains Tm2 through part of the carboxyl tail, overlapping with the 5' genomic clone by 20 nts. (sharing the unique HincII site at position 196 in FIG. 3); and a 0.6 kb PstI fragment from the second h1 genomic clone, which contains the carboxyl tail, the stop codon and ≈0.2 kb of 3' UT sequence, and overlapping with the hH cDNA clone (sharing the unique Pst I site within the carboxyl tail at position 1038 in FIGS. 3A-3G).

The resulting genomic/cDNA/genomic construct contains an open reading frame of 1401 bp and encoding a protein of 466 aa in length, having a molecular weight of ≈51,000 daltons. Hydropathy analysis of the protein is consistent with a putative topography of seven transmembrane domains, as indicated for the previously described human α1a and α1b receptors and indicative of the G protein-coupled receptor family. Sequence analysis revealed that clone α1c/EXJ was most related to adrenergic receptor because it contained the structural features commonly found among the adrenergic receptor family of receptors, as described for the α1a receptor above. Other features of this human α1c receptor gene is the presence of three potential sites for N-linked glycosylation in the amino terminus, at the same position described for the bovine α1c receptor (asparagine residues 7, 13 and 22 in FIG. 3A-3G) (20). Several threonines and serines exist in the second and third cytoplasmic loops of this α1c receptor, which may serve as potential sites for protein kinases and phosphorylation.

                  TABLE 1     ______________________________________     Competition of adrenergic agonists and antagonits for the binding     of [.sup.3 H]prazosin to membranes prepared from LM(tk.sup.-) cells     expressing the human α1a, α1b, and α1c-adrenergic     receptor     cDNA. Membrane preparations from stabily transfecetd cell lines     increasing concentrations of various agonists or antagonists as     described under "Materials and Methods". Data is shown as the     mean ± S.E.M. of the binding parameters estimated by a     computerized non-linear regression analysis obtained in three     independent experiments each performed in triplicate.              pKi              α1a α1b  α1c     ______________________________________     AGONISTS     Norepinephrine                6.633 ± 0.12                            5.614 ± 0.09                                       5.747 ± 0.18     Epinephrine                6.245 ± 0.10                            5.297 ± 0.15                                       5.511 ± 0.13     Oxymetazoline                5.903 ± 0.16                            5.919 ± 0.07                                       7.691 ± 0.10     Naphazoline                6.647 ± 0.18                            6.155 ± 0.04                                       6.705 ± 0.22     Xylometazoline                5.913 ± 0.20                            6.096 ± 0.30                                       7.499 ± 0.19     ANTAGONISTS     Prazosin   9.479 ± 0.19                            9.260 ± 0.23                                       9.234 ± 0.13     WB-4101    8.828 ± 0.12                            7.909 ± 0.13                                       9.080 ± 0.09     (+) Niguldipine                6.643 ± 0.10                            6.937 ± 0.12                                       8.693 ± 0.18     Indoramin  6.629 ± 0.09                            7.347 ± 0.17                                       8.341 ± 0.25     5-Methyl Urapidil                7.795 ± 0.15                            6.603 ± 0.09                                       8.160 ± 0.11     HEAT       7.857 ± 0.13                            8.474 ± 0.10                                       8.617 ± 0.10     Urapidil   6.509 ± 0.18                            5.932 ± 0.11                                       6.987 ± 0.14     Rauwolscine                5.274 ± 0.12                            4.852 ± 0.08                                       4.527 ± 0.11     ______________________________________

Pharmacological Analysis: To further assess the functional identity of the cloned cDNA the coding regions were subcloned into the pCEXV-3 expression vector, and LM(tk-) cell lines stably expressing the human cDNA encoding each of the three α1-ARs were established. Membrane preparations of these cell lines showed high affinity binding of [³ H]prazosin, with Kd values of 0.21±0.03 nM (Bmax=0.73±0.04 pmol/mg prot), 0.88±0.1 nM (Bmax=4.59±0.21 pmol/mg prot) and 0.39±0.08 nM (Bmax=1.9±0.04 pmol/mg prot) for the cells expressing the α1a, α1b, and α1c-ARs respectively. In contrast in competition binding experiments rauwolscine showed extremely low affinity at the three cloned receptors (Table 1), consistent with their identity as α1-AR. The α-adrenergic agonists NE and epinephrine were found to be 6 and 5-fold respectively, more potent at the human α1a-AR, conversely the imidazoline derivatives such as oxymetazoline and xylometazoline showed 52-fold higher potency at the α1c-AR. Similarly, several antagonists showed marked differences in their potency to inhibit [³ H]prazosin binding from the cloned human α1 receptors subtypes. The selective antagonists WB-4101 and 5-methylurapidil showed high affinity for the human α1c subtype (0.8 and 7 nM respectively), followed by less than 2-fold lower potency at the human α1a and at least an order of magnitude (15 and 36-fold respectively) lower potency at the human α1b-AR. Similarly, indoramin was 50 and 10-fold more potent at the α1c than at the α1a and α1b respectively. The calcium channel blocker (+)-niguldipine showed the highest selectivity for the three α1-AR subtypes, displacing [³ H]prazosin 112 and 57-fold more potently from the α1c than from α1a and α1b transfected cells respectively.

                  TABLE 2     ______________________________________     Receptor-mediated formation of [.sup.3 H]IP in cell lines transfected     with the human α1-adrenergic receptors cDNA. Cell lines stably     expressing the human α1-adrenergic receptors were obtained and     the IP formation was measured in the absence or presence of     10 μM norepinephrine (NE) in the presence of 10 nM LiCl as     described under "Material and Methods". Data are shown as     mean ± S.E.M. of three independent experiments performed     in triplicate.                                       Receptor                                       .sup.a Density                [.sup.3 H]IP Fold      pmol/mg     Cell Line  dpm/dish     Stimulation                                       Prot     ______________________________________     293 α1a                     3.30     Control    288 ± 29     NE         3646 ± 144                             13     CHO α1b                     0.49     Control    1069 ± 26     NE         5934 ± 309                              6     NIH3T3 α1c                  0.24     Control    722 ± 61     NE         13929 ± 1226                             19     ______________________________________      .sup.a Determined by [.sup.3 H]Prazosin binding.

The formation of [³ H]IP was measured in 293, CHO, and NIH3T3 cell stably expressing the cloned human α1a, α1b, α1c-ARs respectively, to assess the functional coupling of these receptors with the activation of phosphatidylinositol specific phospholipase C (PI-PLC). As shown in Table 2, the adrenergic agonist NE (10 μM) activated the formation of IP by 13 fold in cells expressing the α1a receptor, and by 5 and 15-fold in cells expressing the α1b and α1c receptors respectively. Furthermore, when cells expressing α1a, α1b and α1c receptors were incubated in the presence of 10 μM NE, a rapid increase of cytosolic calcium was observed. The response was characterized by an early peak, followed by a plateau that slowly declined towards resting calcium levels (FIG. 7). The concentration of [Ca²⁺ ]_(i), was increased by 172±33 n=6 170±48 (n=6) and 224±79 nM (n=6) in cell lines transfected with the α1a, α1b and α1c receptor respectively. The changes in [Ca²⁺ ]_(i) induced by NE were suppressed by preincubation of the cells with 10 nM prazosin, indicating that the calcium response was mediated by α1-ARs.

We have cloned DNA representing three α1-ARs subtypes (α1a, α1b, and α1c) from human brain cDNA and genomic DNA. Of all known G protein-coupled receptor sequences (EMBL/Genbank Data Base), the greatest homology was found between α1a/EXJ and the rat α1a AR (12), rat α1d AR (16) and a previously reported putative human "α1a" adrenergic receptor (H318/3)(2). Comparison of the human α1a deduced aa sequence with known α1a ARs indicates the greatest concentration of identical aa to be in the transmembrane domains. In these Tm regions, the percentage of identity for the human α1a AR is 98% compared to rat α1a AR (12) (this is approximately the same for rat α1d since rat α1d AR is the same as rat α1a AR, except for two amino acid differences), 100% with the previously reported H318/3, 78% with the human α1b receptor (see below), and 69% with the human α1c receptor (see below), which is typical among subtypes. When considering the full-length proteins, the percent identity drops and is only 50% for the human α1b and 49% for the human α1c receptor. Both the alignment (see FIG. 4) and percent identity of this human α1a sequence, relative to other members of the AR family strongly suggest that this is a new receptor and is the human species homolog of the rat α1a receptor.

FIG. 4 shows a comparison between the deduced aa sequence of α1a/EXJ and the sequences of rat α1a and HAR. An overall homology of 83.5% aa identity with rat α1a and 86.5% aa identity with the previously published H318/3 clone was observed, suggesting that our human α1a receptor is not any more related to the previously published putative human "α1a" than it is to the rat α1a receptor. In fact, in support of this conclusion, is the fact that the overall aa homology of rat α1a receptor with our human α1a receptor is 83.5% but is only 72% compared to the H318/3 receptor. The main differences between our human α1a receptor and the previously reported "α1a" receptor in relation to the rat α1a are indicated in FIG. 4. Most notably are the differences observed at both the amino and carboxyl ends of the receptor. Specifically, both our human α1a and rat α1a use the starting MET aa at position 1 (see FIG. 4) whereas the previously published H318/3 uses the starting MET 48 aa downstream. Also, the amino terminus of the H318/3 clone is completely divergent from either rat α1a or our human α1a receptor until about 12 aa upstream of Tm1 where significant homology begins. Similarly, in the carboxyl tail, the homology of H318/3 diverges ≈90 aa upstream-from the stop codon of either rat or our human α1a receptor and instead, uses a stop codon 30 aa upstream from the stop codon on either of these receptors. Finally, the H318/3 clone has an amino terminal extracellular region that does not contain potential sites for N-linked glycosylation (2), in contrast to the rat α1a or our human α1a receptor, which contains two potential sites (12, see also FIG. 1 and above). Thus, these data strongly suggest that our human α1a receptor is different in sequence from the previously reported putative human "α1a" (H318/3) but is more related to the previously published rat α1a receptor. Interestingly, the rat α1a aa sequence diverges from both human α1a receptors for ≈65 aa in the carboxyl tail (position 434-508 in FIG. 1); however, homology is seen again in our human α1a receptor but not with H318/3, downstream from this region.

The cloning of different α1 receptor subtypes permits analysis of both the pharmacological and functional properties of adrenergic receptors. The human α1b/pCEXV clone exhibited the greatest homology with the rat and hamster α1b receptors, out of all known G protein-coupled receptor clones (EMBL/Genbank Data Bank). Comparison of the human α1b deduced aa sequence with known α1 ARs indicates the greatest homology in the transmembrane regions. In these Tm regions, the percent identity for the human α1b AR is 99% compared to either rat (25) or hamster (4) α1b receptor 78% with human α1a receptor and 75% with human α1c receptor, which is typical among subtypes. When analyzing the full-length proteins, the percent identity slightly drops and is 94.5% compared to rat α1b, 95.5% compared to hamster α1b receptor, 50% compared to human α1a and 51% compared to human α1c receptor. Both the alignment (see FIG. 5) and percent identity of this human α1b sequence, relative to other members of the AR family, strongly suggest that this clone represents a new receptor and is the human species homologue of the rat/hamster α1b receptor. FIG. 5 shows a comparison between the deduced amino acid sequence of α1b/pcEXV and the aa sequence of rat α1b and hamster α1b receptors.

A third human adrenergic receptor clone, α1c/EXJ, showed the greatest homology with the bovine α1c AR gene (20), from all known G protein-coupled receptor sequences (EMBL/Genbank Data Bank). Comparison of the human α1c deduced aa sequence with the α1 ARs indicates the greatest homology to be in the transmembrane regions. In these Tm regions, the percent identity for the human α1c AR is 97% compared to the bovine α1c AR (20), 75% with human α1b receptor and 69% with human α1a receptor, which is typical among subtypes. When one examines the full-length proteins, the percent identity drops and is only 51% compared to either the human α1b or human α1a receptor. FIG. 6 shows a comparison between the deduced amino acid sequence of α1c/EXJ and the aa sequence of bovine α1c. An overall homology of 92% aa identity with bovine α1c receptor was observed. Both the alignment (see FIG. 6) and percent identity of this human α1c sequence, relative to other members of the AR family, strongly suggest that this clone represents a new receptor and is the human species homologue of the bovine α1c receptor.

The stable expression of the three cloned human α1 receptors enabled the characterization of their pharmacological as well as their functional properties and allowed identification of certain unique features of the human receptors, not predicted from previous data. The rank-order of potency of known α-adrenergic agonists and antagonists to compete with [³ H]prazosin in binding assays, confirmed that the cloned cDNAs encode three human receptors of the α1-AR family. Moreover, the potencies of selective antagonists such as WB-4101 and 5-methyl-urapidil at the three human α1-receptors were found to be in close agreement with the potencies of these antagonists at the cloned rat α1a, hamster α1b, and bovine α1c (4, 12, 20). These results suggest that the sequence homology between the three mammalian α1 receptors resulted in a conservation of their pharmacological properties across different species. In the past the pharmacological characterization of α1-adrenergic receptors took advantage of the existence of selective antagonists such as WB-4101 and 5-methyl-urapidil that bind with high affinity to a subset of α1-receptors classified as α1A (9, 15). Our results using these selective antagonists indicate that these antagonists bind with similar affinity to both human α1a and α1c-receptors, and that they can only discriminate between either of these two subtypes and the α1b receptor. The calcium channel blocker (+)-niguldipine was found to bind with high affinity to a subset of α1-receptors also labeled by [³ H]5-methyl-urapidil in rat brain, thus defining this antagonist as α1A selective (8). The high affinity of the human α1c receptor for (+)-niguldipine and the fact that it binds to the human α1a and α1b subtypes, with at least an order of magnitude lower affinity, strongly supports the notion that the human α1c gene encodes the pharmacological α1A-receptor subtype. The possibility that this also holds true in the rat, is suggested by the fact that the potency of (+)niguldipine for the rat α1a clone is also at least an order of magnitude lower than that found for this antagonist in rat tissues. Moreover, in spite of the earlier reports on the absence of the bovine α1c cognate in rat tissues (20, 21), pharmacological evidence suggests that this species express an α1 receptor similar to the cloned α1c receptor. These data altogether indicate that in trying to match the pharmacological subclassification of the α1-ARs with the evidence from molecular cloning studies, the initial assignment of the cloned rat α1a receptor with the α1A receptor subtype was inadequate. Recently, a rat cDNA clone 99.8% homologous to the rat α1a-receptor, was described as a novel α1d subtype (16); however, this incorrect classification was due to the poor correlation between the affinities of α1A-selective antagonists in tissue preparations versus the cloned rat α1a receptor.

The three human α1 receptor subtypes were able to induce the formation of IP, consistent with the known functional coupling of α1-ARs, through a GTP-dependent protein to the activation of PI-PLC. In addition we demonstrated that upon receptor activation by adrenergic agonists, the three human α1 receptor subtypes induced transient changes in [Ca²⁺ ]_(i). Consistent with the mobilization of calcium from intracellular stores by inositol-1,3,5 triphosphate, released by the receptor-mediated activation of PI-PLC.

We have cloned and expressed three human cDNA that encode functional α1-ARs. This three transcripts display significant pharmacologic as well as molecular features to constitute distinct α1-AR subtypes. In sharp contrast with the restricted expression of the rat and bovine transcripts, our findings indicate that species homologs of the three α1-ARs are expressed in human tissues. These findings together with recent reports on the dissimilar tissue distribution of the α1b and α1c receptor cognates between animal species such as rat and rabbit (21), commonly used in the development of novel α1-adrenergic agents, emphasize the need to study the pharmacological properties of the human α1-receptors. In this regard, the results from this study on the selectivity of clinically effective antihypertensives such as indoramin, as well as vasoconstrictors such as oxymetazoline and xylometazoline for the human α1c-AR, suggest a potential role for this α1-receptor subtype in the physiological control of vascular tone in the human. Thus, the availability of cell lines expressing each of the human α1-receptor subtypes constitute a unique tool in the design of subtype specific agonists and antagonists, that can be targeted to selective therapeutic applications. Of specific interest for therapeutics are subtype selective alpha-1 antagonists for the treatment of Benign Prostatic Hypertrophy and subtype selective alpha-1 agonists for the treatment of nasal congestion. In each case, a more selective drug is expected to reduce the side effects which presently limit this avenue of therapy. The development of subtype selective alpha-1 agonists may also lead to more effective treatment of urinary incontinence.

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    __________________________________________________________________________     SEQUENCE LISTING     (1) GENERAL INFORMATION:     (iii) NUMBER OF SEQUENCES: 6     (2) INFORMATION FOR SEQ ID NO:1:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 2140 base pairs     (B) TYPE: nucleic acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: unknown     (ii) MOLECULE TYPE: DNA (genomic)     (iii) HYPOTHETICAL: N     (iv) ANTI-SENSE: N     (ix) FEATURE:     (A) NAME/KEY: CDS     (B) LOCATION: 178..1893     (D) OTHER INFORMATION:     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:     CCGGGCCAGGCACGTCCGCTCTCGGACAGCCGCTCCGCGTCACAGGAACTTGGGCAGGAC60     CCGACGGGACCCGTGCGCGGAGCTGCATCTGGAGCCCCGCGGCTATGCCCTGTGCTCCCC120     TCCTGCCGGCCGCTCGTTCTGTGCCCCCGGCCCGGCCACCGACGGCCGCGCGTTGAG177     ATGACTTTCCGCGATCTCCTGAGCGTCAGTTTCGAGGGACCCCGCCCG225     MetThrPheArgAspLeuLeuSerValSerPheGluGlyProArgPro     151015     GACAGCAGCGCAGGGGGCTCCAGCGCGGGCGGCGGCGGGGGCAGCGCG273     AspSerSerAlaGlyGlySerSerAlaGlyGlyGlyGlyGlySerAla     202530     GGCGGCGCGGCCCCCTCGGAGGGCCCGGCGGTGGGCGGCGTGCCGGGG321     GlyGlyAlaAlaProSerGluGlyProAlaValGlyGlyValProGly     354045     GGCGCGGGCGGCGGCGGCGGCGTGGTGGGCGCAGGCAGCGGCGAGGAC369     GlyAlaGlyGlyGlyGlyGlyValValGlyAlaGlySerGlyGluAsp     505560     AACCGGAGCTCCGCGGGGGAGCCGGGGAGCGCGGGCGCGGGCGGCGAC417     AsnArgSerSerAlaGlyGluProGlySerAlaGlyAlaGlyGlyAsp     65707580     GTGAATGGCACGGCGGCCGTCGGGGGACTGGTGGTGAGCGCGCAGGGC465     ValAsnGlyThrAlaAlaValGlyGlyLeuValValSerAlaGlnGly     859095     GTGGGCGTGGGCGTCTTCCTGGCAGCCTTCATCCTTATGGCCGTGGCA513     ValGlyValGlyValPheLeuAlaAlaPheIleLeuMetAlaValAla     100105110     GGTAACCTGCTTGTCATCCTCTCAGTGGCCTGCAACCGCCACCTGCAG561     GlyAsnLeuLeuValIleLeuSerValAlaCysAsnArgHisLeuGln     115120125     ACCGTCACCAACTATTTCATCGTGAACCTGGCCGTGGCCGACCTGCTG609     ThrValThrAsnTyrPheIleValAsnLeuAlaValAlaAspLeuLeu     130135140     CTGAGCGCCACCGTACTGCCCTTCTCGGCCACCATGGAGGTTCTGGGC657     LeuSerAlaThrValLeuProPheSerAlaThrMetGluValLeuGly     145150155160     TTCTGGGCCTTTGGCCGCGCCTTCTGCGACGTATGGGCCGCCGTGGAC705     PheTrpAlaPheGlyArgAlaPheCysAspValTrpAlaAlaValAsp     165170175     GTGCTGTGCTGCACGGCCTCCATCCTCAGCCTCTGCACCATCTCCGTG753     ValLeuCysCysThrAlaSerIleLeuSerLeuCysThrIleSerVal     180185190     GACCGGTACGTGGGCGTGCGCCACTCACTCAAGTACCCAGCCATCATG801     AspArgTyrValGlyValArgHisSerLeuLysTyrProAlaIleMet     195200205     ACCGAGCGCAAGGCGGCCGCCATCCTGGCCCTGCTCTGGGTCGTAGCC849     ThrGluArgLysAlaAlaAlaIleLeuAlaLeuLeuTrpValValAla     210215220     CTGGTGGTGTCCGTAGGGCCCCTGCTGGGCTGGAAGGAGCCCGTGCCC897     LeuValValSerValGlyProLeuLeuGlyTrpLysGluProValPro     225230235240     CCTGACGAGCGCTTCTGCGGTATCACCGAGGAGGCGGGCTACGCTGTC945     ProAspGluArgPheCysGlyIleThrGluGluAlaGlyTyrAlaVal     245250255     TTCTCCTCCGTGTGCTCCTTCTACCTGCCCATGGCGGTCATCGTGGTC993     PheSerSerValCysSerPheTyrLeuProMetAlaValIleValVal     260265270     ATGTACTGCCGCGTGTACGTGGTCGCGCGCAGCACCACGCGCAGCCTC1041     MetTyrCysArgValTyrValValAlaArgSerThrThrArgSerLeu     275280285     GAGGCAGGCGTCAAGCGCGAGCGAGGCAAGGCCTCCGAGGTGGTGCTG1089     GluAlaGlyValLysArgGluArgGlyLysAlaSerGluValValLeu     290295300     CGCATCCACTGTCGCGGCGCGGCCACGGGCGCCGACGGGGCGCACGGC1137     ArgIleHisCysArgGlyAlaAlaThrGlyAlaAspGlyAlaHisGly     305310315320     ATGCGCAGCGCCAAGGGCCACACCTTCCGCAGCTCGCTCTCCGTGCGC1185     MetArgSerAlaLysGlyHisThrPheArgSerSerLeuSerValArg     325330335     CTGCTCAAGTTCTCCCGTGAGAAGAAAGCGGCCAAGACTCTGGCCATC1233     LeuLeuLysPheSerArgGluLysLysAlaAlaLysThrLeuAlaIle     340345350     GTCGTGGGTGTCTTCGTGCTCTGCTGGTTCCCTTTCTTCTTTGTCCTG1281     ValValGlyValPheValLeuCysTrpPheProPhePhePheValLeu     355360365     CCGCTCGGCTCCTTGTTCCCGCAGCTGAAGCCATCGGAGGGCGTCTTC1329     ProLeuGlySerLeuPheProGlnLeuLysProSerGluGlyValPhe     370375380     AAGGTCATCTTCTGGCTCGGCTACTTCAACAGCTGCGTGAACCCGCTC1377     LysValIlePheTrpLeuGlyTyrPheAsnSerCysValAsnProLeu     385390395400     ATCTACCCCTGTTCCAGCCGCGAGTTCAAGCGCGCCTTCCTCCGTCTC1425     IleTyrProCysSerSerArgGluPheLysArgAlaPheLeuArgLeu     405410415     CTGCGCTGCCAGTGCCGTCGTCGCCGGCGCCGCCGCCCTCTCTGGCGT1473     LeuArgCysGlnCysArgArgArgArgArgArgArgProLeuTrpArg     420425430     GTCTACGGCCACCACTGGCGGGCCTCCACCAGCGGCCTGCGCCAGGAC1521     ValTyrGlyHisHisTrpArgAlaSerThrSerGlyLeuArgGlnAsp     435440445     TGCGCCCCGAGTTCGGGCGACGCGCCCCCCGGAGCGCCGCTGGCCCTC1569     CysAlaProSerSerGlyAspAlaProProGlyAlaProLeuAlaLeu     450455460     ACCGCGCTCCCCGACCCCGACCCCGAACCCCCAGGCACGCCCGAGATG1617     ThrAlaLeuProAspProAspProGluProProGlyThrProGluMet     465470475480     CAGGCTCCGGTCGCCAGCCGTCGAAAGCCACCCAGCGCCTTCCGCGAG1665     GlnAlaProValAlaSerArgArgLysProProSerAlaPheArgGlu     485490495     TGGAGGCTGCTGGGGCCGTTCCGGAGACCCACGACCCAGCTGCGCGCC1713     TrpArgLeuLeuGlyProPheArgArgProThrThrGlnLeuArgAla     500505510     AAAGTCTCCAGCCTGTCGCACAAGATCCGCGCCGGGGGCGCGCAGCGC1761     LysValSerSerLeuSerHisLysIleArgAlaGlyGlyAlaGlnArg     515520525     GCAGAGGCAGCGTGCGCCCAGCGCTCAGAGGTGGAGGCTGTGTCCCTA1809     AlaGluAlaAlaCysAlaGlnArgSerGluValGluAlaValSerLeu     530535540     GGCGTCCCACACGAGGTGGCCGAGGGCGCCACCTGCCAGGCCTACGAA1857     GlyValProHisGluValAlaGluGlyAlaThrCysGlnAlaTyrGlu     545550555560     TTGGCCGACTACAGCAACCTACGGGAGACCGATATTTAAGGACCCC1903     LeuAlaAspTyrSerAsnLeuArgGluThrAspIle     565570     AGAGCTAGGCCGCGGAGTGTGCTGGGCTTGGGGGTAAGGGGGACCAGAGAGGCGGGCTGG1963     TGTTCTAAGAGCCCCCGTGCAAATCGGAGACCCGGAAACTGATCAGGGCAGCTGCTCTGT2023     GACATCCCTGAGGAACTGGGCAGAGCTTGAGGCTGGAGCCCTTGAAAGGTGAAAAGTAGT2083     GGGGCCCCCTGCTGGACTCAGGTGCCCAGAACTCTTTTCTTAGAAGGGAGAGGCTGC2140     (2) INFORMATION FOR SEQ ID NO:2:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 572 amino acids     (B) TYPE: amino acid     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: protein     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:     MetThrPheArgAspLeuLeuSerValSerPheGluGlyProArgPro     151015     AspSerSerAlaGlyGlySerSerAlaGlyGlyGlyGlyGlySerAla     202530     GlyGlyAlaAlaProSerGluGlyProAlaValGlyGlyValProGly     354045     GlyAlaGlyGlyGlyGlyGlyValValGlyAlaGlySerGlyGluAsp     505560     AsnArgSerSerAlaGlyGluProGlySerAlaGlyAlaGlyGlyAsp     65707580     ValAsnGlyThrAlaAlaValGlyGlyLeuValValSerAlaGlnGly     859095     ValGlyValGlyValPheLeuAlaAlaPheIleLeuMetAlaValAla     100105110     GlyAsnLeuLeuValIleLeuSerValAlaCysAsnArgHisLeuGln     115120125     ThrValThrAsnTyrPheIleValAsnLeuAlaValAlaAspLeuLeu     130135140     LeuSerAlaThrValLeuProPheSerAlaThrMetGluValLeuGly     145150155160     PheTrpAlaPheGlyArgAlaPheCysAspValTrpAlaAlaValAsp     165170175     ValLeuCysCysThrAlaSerIleLeuSerLeuCysThrIleSerVal     180185190     AspArgTyrValGlyValArgHisSerLeuLysTyrProAlaIleMet     195200205     ThrGluArgLysAlaAlaAlaIleLeuAlaLeuLeuTrpValValAla     210215220     LeuValValSerValGlyProLeuLeuGlyTrpLysGluProValPro     225230235240     ProAspGluArgPheCysGlyIleThrGluGluAlaGlyTyrAlaVal     245250255     PheSerSerValCysSerPheTyrLeuProMetAlaValIleValVal     260265270     MetTyrCysArgValTyrValValAlaArgSerThrThrArgSerLeu     275280285     GluAlaGlyValLysArgGluArgGlyLysAlaSerGluValValLeu     290295300     ArgIleHisCysArgGlyAlaAlaThrGlyAlaAspGlyAlaHisGly     305310315320     MetArgSerAlaLysGlyHisThrPheArgSerSerLeuSerValArg     325330335     LeuLeuLysPheSerArgGluLysLysAlaAlaLysThrLeuAlaIle     340345350     ValValGlyValPheValLeuCysTrpPheProPhePhePheValLeu     355360365     ProLeuGlySerLeuPheProGlnLeuLysProSerGluGlyValPhe     370375380     LysValIlePheTrpLeuGlyTyrPheAsnSerCysValAsnProLeu     385390395400     IleTyrProCysSerSerArgGluPheLysArgAlaPheLeuArgLeu     405410415     LeuArgCysGlnCysArgArgArgArgArgArgArgProLeuTrpArg     420425430     ValTyrGlyHisHisTrpArgAlaSerThrSerGlyLeuArgGlnAsp     435440445     CysAlaProSerSerGlyAspAlaProProGlyAlaProLeuAlaLeu     450455460     ThrAlaLeuProAspProAspProGluProProGlyThrProGluMet     465470475480     GlnAlaProValAlaSerArgArgLysProProSerAlaPheArgGlu     485490495     TrpArgLeuLeuGlyProPheArgArgProThrThrGlnLeuArgAla     500505510     LysValSerSerLeuSerHisLysIleArgAlaGlyGlyAlaGlnArg     515520525     AlaGluAlaAlaCysAlaGlnArgSerGluValGluAlaValSerLeu     530535540     GlyValProHisGluValAlaGluGlyAlaThrCysGlnAlaTyrGlu     545550555560     LeuAlaAspTyrSerAsnLeuArgGluThrAspIle     565570     (2) INFORMATION FOR SEQ ID NO:3:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 1738 base pairs     (B) TYPE: nucleic acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: unknown     (ii) MOLECULE TYPE: DNA (genomic)     (iii) HYPOTHETICAL: N     (iv) ANTI-SENSE: N     (ix) FEATURE:     (A) NAME/KEY: CDS     (B) LOCATION: 124..1683     (D) OTHER INFORMATION:     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:3:     GCCAGGAGGGCGCCTCTGGGAAGAAGACCACGGGGGAAGCAAAGTTTCAGGGCAGCTGAG60     GAGCCTTCGCCGCAGCCCTTCCGAGCCCAATCATCCCCCAGGCTATGGAGGGCGGACTCT120     AAGATGAATCCCGACCTGGACACCGGCCACAACACATCAGCACCTGCC168     MetAsnProAspLeuAspThrGlyHisAsnThrSerAlaProAla     151015     CACTGGGGAGAGTTGAAAAATGCCAACTTCACTGGCCCCAACCAGACC216     HisTrpGlyGluLeuLysAsnAlaAsnPheThrGlyProAsnGlnThr     202530     TCGAGCAACTCCACACTGCCCCAGCTGGACATCACCAGGGCCATCTCT264     SerSerAsnSerThrLeuProGlnLeuAspIleThrArgAlaIleSer     354045     GTGGGCCTGGTGCTGGGCGCCTTCATCCTCTTTGCCATCGTGGGCAAC312     ValGlyLeuValLeuGlyAlaPheIleLeuPheAlaIleValGlyAsn     505560     ATCCTAGTCATCTTGTCTGTGGCCTGCAACCGGCACCTGCGGACGCCC360     IleLeuValIleLeuSerValAlaCysAsnArgHisLeuArgThrPro     657075     ACCAACTACTTCATTGTCAACCTGGCCATGGCCGACCTGCTGTTGAGC408     ThrAsnTyrPheIleValAsnLeuAlaMetAlaAspLeuLeuLeuSer     80859095     TTCACCGTCCTGCCCTTCTCAGCGGCCCTAGAGGTGCTCGGCTACTGG456     PheThrValLeuProPheSerAlaAlaLeuGluValLeuGlyTyrTrp     100105110     GTGCTGGGGCGGATCTTCTGTGACATCTGGGCAGCCGTGGATGTCCTG504     ValLeuGlyArgIlePheCysAspIleTrpAlaAlaValAspValLeu     115120125     TGCTGCACAGCGTCCATTCTGAGCCTGTGCGCCATCTCCATCGATCGC552     CysCysThrAlaSerIleLeuSerLeuCysAlaIleSerIleAspArg     130135140     TACATCGGGGTGCGCTACTCTCTGCAGTATCCCACGCTGGTCACCCGG600     TyrIleGlyValArgTyrSerLeuGlnTyrProThrLeuValThrArg     145150155     AGGAAGGCCATCTTGGCGCTGCTCAGTGTCTGGGTCTTGTCCACCGTC648     ArgLysAlaIleLeuAlaLeuLeuSerValTrpValLeuSerThrVal     160165170175     ATCTCCATCGGGCCTCTCCTTGGGTGGAAGGAGCCGGCACCCAACGAT696     IleSerIleGlyProLeuLeuGlyTrpLysGluProAlaProAsnAsp     180185190     GACAAGGAGTGCGGGGTCACCGAAGAACCCTTCTATGCCCTCTTCTCC744     AspLysGluCysGlyValThrGluGluProPheTyrAlaLeuPheSer     195200205     TCTCTGGGCTCCTTCTACATCCCTCTGGCGGTCATTCTAGTCATGTAC792     SerLeuGlySerPheTyrIleProLeuAlaValIleLeuValMetTyr     210215220     TGCCGTGTCTATATAGTGGCCAAGAGAACCACCAAGAACCTAGAGGCA840     CysArgValTyrIleValAlaLysArgThrThrLysAsnLeuGluAla     225230235     GGAGTCATGAAGGAGATGTCCAACTCCAAGGAGCTGACCCTGAGGATC888     GlyValMetLysGluMetSerAsnSerLysGluLeuThrLeuArgIle     240245250255     CATTCCAAGAACTTTCACGAGGACACCCTTAGCAGTACCAAGGCCAAG936     HisSerLysAsnPheHisGluAspThrLeuSerSerThrLysAlaLys     260265270     GGCCACAACCCCAGGAGTTCCATAGCTGTCAAACTTTTTAAGTTCTCC984     GlyHisAsnProArgSerSerIleAlaValLysLeuPheLysPheSer     275280285     AGGGAAAAGAAAGCAGCTAAGACGTTGGGCATTGTGGTCGGTATGTTC1032     ArgGluLysLysAlaAlaLysThrLeuGlyIleValValGlyMetPhe     290295300     ATCTTGTGCTGGCTACCCTTCTTCATCGCTCTACCGCTTGGCTCCTTG1080     IleLeuCysTrpLeuProPhePheIleAlaLeuProLeuGlySerLeu     305310315     TTCTCCACCCTGAAGCCCCCCGACGCCGTGTTCAAGGTGGTGTTCTGG1128     PheSerThrLeuLysProProAspAlaValPheLysValValPheTrp     320325330335     CTGGGCTACTTCAACAGCTGCCTCAACCCCATCATCTACCCATGCTCC1176     LeuGlyTyrPheAsnSerCysLeuAsnProIleIleTyrProCysSer     340345350     AGCAAGGAGTTCAAGCGCGCTTTCGTGCGCATCCTCGGGTGCCAGTGC1224     SerLysGluPheLysArgAlaPheValArgIleLeuGlyCysGlnCys     355360365     CGCGGCCGCGGCCGCCGCCGACGCCGCCGCCGCCGTCGCCTGGGCGGC1272     ArgGlyArgGlyArgArgArgArgArgArgArgArgArgLeuGlyGly     370375380     TGCGCCTACACCTACCGGCCGTGGACGCGCGGCGGCTCGCTGGAGCGC1320     CysAlaTyrThrTyrArgProTrpThrArgGlyGlySerLeuGluArg     385390395     TCGCAGTCGCGCAAGGACTCGCTGGACGACAGCGGCAGCTGCCTGAGC1368     SerGlnSerArgLysAspSerLeuAspAspSerGlySerCysLeuSer     400405410415     GGCAGCCAGCGGACCCTGCCCTCGGCCTCGCCGAGCCCGGGCTACCTG1416     GlySerGlnArgThrLeuProSerAlaSerProSerProGlyTyrLeu     420425430     GGCCGCGGCGCGCCACCGCCAGTCGAGCTGTGCGCCTTCCCCGAGTGG1464     GlyArgGlyAlaProProProValGluLeuCysAlaPheProGluTrp     435440445     AAGGCGCCCGGCGCCCTCCTGAGCCTGCCCGCGCCTGAGCCCCCCGGC1512     LysAlaProGlyAlaLeuLeuSerLeuProAlaProGluProProGly     450455460     CGCCGCGGCCGCCACGACTCGGGCCCGCTCTTCACCTTCAAGCTCCTG1560     ArgArgGlyArgHisAspSerGlyProLeuPheThrPheLysLeuLeu     465470475     ACCGAGCCCGAGAGCCCCGGGACCGACGGCGGCGCCAGCAACGGAGGC1608     ThrGluProGluSerProGlyThrAspGlyGlyAlaSerAsnGlyGly     480485490495     TGCGAGGCCGCGGCCGACGTGGCCAACGGGCAGCCGGGCTTCAAAAGC1656     CysGluAlaAlaAlaAspValAlaAsnGlyGlnProGlyPheLysSer     500505510     AACATGCCCCTGGCGCCCGGGCAGTTTTAGGGCCCCCGTGCGCAGCT1703     AsnMetProLeuAlaProGlyGlnPhe     515520     TTCTTTCCCTGGGGAGGAAAACATCGTGGGGGGGA1738     (2) INFORMATION FOR SEQ ID NO:4:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 520 amino acids     (B) TYPE: amino acid     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: protein     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:4:     MetAsnProAspLeuAspThrGlyHisAsnThrSerAlaProAlaHis     151015     TrpGlyGluLeuLysAsnAlaAsnPheThrGlyProAsnGlnThrSer     202530     SerAsnSerThrLeuProGlnLeuAspIleThrArgAlaIleSerVal     354045     GlyLeuValLeuGlyAlaPheIleLeuPheAlaIleValGlyAsnIle     505560     LeuValIleLeuSerValAlaCysAsnArgHisLeuArgThrProThr     65707580     AsnTyrPheIleValAsnLeuAlaMetAlaAspLeuLeuLeuSerPhe     859095     ThrValLeuProPheSerAlaAlaLeuGluValLeuGlyTyrTrpVal     100105110     LeuGlyArgIlePheCysAspIleTrpAlaAlaValAspValLeuCys     115120125     CysThrAlaSerIleLeuSerLeuCysAlaIleSerIleAspArgTyr     130135140     IleGlyValArgTyrSerLeuGlnTyrProThrLeuValThrArgArg     145150155160     LysAlaIleLeuAlaLeuLeuSerValTrpValLeuSerThrValIle     165170175     SerIleGlyProLeuLeuGlyTrpLysGluProAlaProAsnAspAsp     180185190     LysGluCysGlyValThrGluGluProPheTyrAlaLeuPheSerSer     195200205     LeuGlySerPheTyrIleProLeuAlaValIleLeuValMetTyrCys     210215220     ArgValTyrIleValAlaLysArgThrThrLysAsnLeuGluAlaGly     225230235240     ValMetLysGluMetSerAsnSerLysGluLeuThrLeuArgIleHis     245250255     SerLysAsnPheHisGluAspThrLeuSerSerThrLysAlaLysGly     260265270     HisAsnProArgSerSerIleAlaValLysLeuPheLysPheSerArg     275280285     GluLysLysAlaAlaLysThrLeuGlyIleValValGlyMetPheIle     290295300     LeuCysTrpLeuProPhePheIleAlaLeuProLeuGlySerLeuPhe     305310315320     SerThrLeuLysProProAspAlaValPheLysValValPheTrpLeu     325330335     GlyTyrPheAsnSerCysLeuAsnProIleIleTyrProCysSerSer     340345350     LysGluPheLysArgAlaPheValArgIleLeuGlyCysGlnCysArg     355360365     GlyArgGlyArgArgArgArgArgArgArgArgArgLeuGlyGlyCys     370375380     AlaTyrThrTyrArgProTrpThrArgGlyGlySerLeuGluArgSer     385390395400     GlnSerArgLysAspSerLeuAspAspSerGlySerCysLeuSerGly     405410415     SerGlnArgThrLeuProSerAlaSerProSerProGlyTyrLeuGly     420425430     ArgGlyAlaProProProValGluLeuCysAlaPheProGluTrpLys     435440445     AlaProGlyAlaLeuLeuSerLeuProAlaProGluProProGlyArg     450455460     ArgGlyArgHisAspSerGlyProLeuPheThrPheLysLeuLeuThr     465470475480     GluProGluSerProGlyThrAspGlyGlyAlaSerAsnGlyGlyCys     485490495     GluAlaAlaAlaAspValAlaAsnGlyGlnProGlyPheLysSerAsn     500505510     MetProLeuAlaProGlyGlnPhe     515520     (2) INFORMATION FOR SEQ ID NO:5:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 1639 base pairs     (B) TYPE: nucleic acid     (C) STRANDEDNESS: single     (D) TOPOLOGY: unknown     (ii) MOLECULE TYPE: DNA (genomic)     (iii) HYPOTHETICAL: N     (iv) ANTI-SENSE: N     (ix) FEATURE:     (A) NAME/KEY: CDS     (B) LOCATION: 126..1523     (D) OTHER INFORMATION:     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:5:     CCAGCCAAACCACTGGCAGGCTCCCTCCAGCCGAGACCTTTTATTCCCGGCTCCCGAGCT60     CCGCCTCCGCGCCAGCCCGGGAGGTGGCCCTGACAGCCGGACCTCGCCCGGCCCCGGCTG120     GGACCATGGTGTTTCTCTCGGGAAATGCTTCCGACAGCTCCAACTGC167     MetValPheLeuSerGlyAsnAlaSerAspSerSerAsnCys     1510     ACCCAACCGCCGGCACCGGTGAACATTTCCAAGGCCATTCTGCTCGGG215     ThrGlnProProAlaProValAsnIleSerLysAlaIleLeuLeuGly     15202530     GTGATCTTGGGGGGCCTCATTCTTTTCGGGGTGCTGGGTAACATCCTA263     ValIleLeuGlyGlyLeuIleLeuPheGlyValLeuGlyAsnIleLeu     354045     GTGATCCTCTCCGTAGCCTGTCACCGACACCTGCACTCAGTCACGCAC311     ValIleLeuSerValAlaCysHisArgHisLeuHisSerValThrHis     505560     TACTACATCGTCAACCTGGCGGTGGCCGACCTCCTGCTCACCTCCACG359     TyrTyrIleValAsnLeuAlaValAlaAspLeuLeuLeuThrSerThr     657075     GTGCTGCCCTTCTCCGCCATCTTCGAGGTCCTAGGCTACTGGGCCTTC407     ValLeuProPheSerAlaIlePheGluValLeuGlyTyrTrpAlaPhe     808590     GGCAGGGTCTTCTGCAACATCTGGGCGGCAGTGGATGTGCTGTGCTGC455     GlyArgValPheCysAsnIleTrpAlaAlaValAspValLeuCysCys     95100105110     ACCGCGTCCATCATGGGCCTCTGCATCATCTCCATCGACCGCTACATC503     ThrAlaSerIleMetGlyLeuCysIleIleSerIleAspArgTyrIle     115120125     GGCGTGAGCTACCCGCTGCGCTACCCAACCATCGTCACCCAGAGGAGG551     GlyValSerTyrProLeuArgTyrProThrIleValThrGlnArgArg     130135140     GGTCTCATGGCTCTGCTCTGCGTCTGGGCACTCTCCCTGGTCATATCC599     GlyLeuMetAlaLeuLeuCysValTrpAlaLeuSerLeuValIleSer     145150155     ATTGGACCCCTGTTCGGCTGGAGGCAGCCGGCCCCCGAGGACGAGACC647     IleGlyProLeuPheGlyTrpArgGlnProAlaProGluAspGluThr     160165170     ATCTGCCAGATCAACGAGGAGCCGGGCTACGTGCTCTTCTCAGCGCTG695     IleCysGlnIleAsnGluGluProGlyTyrValLeuPheSerAlaLeu     175180185190     GGCTCCTTCTACCTGCCTCTGGCCATCATCCTGGTCATGTACTGCCGC743     GlySerPheTyrLeuProLeuAlaIleIleLeuValMetTyrCysArg     195200205     GTCTACGTGGTGGCCAAGAGGGAGAGCCGGGGCCTCAAGTCTGGCCTC791     ValTyrValValAlaLysArgGluSerArgGlyLeuLysSerGlyLeu     210215220     AAGACCGACAAGTCGGACTCGGAGCAAGTGACGCTCCGCATCCATCGG839     LysThrAspLysSerAspSerGluGlnValThrLeuArgIleHisArg     225230235     AAAAACGCCCCGGCAGGAGGCAGCGGGATGGCCAGCGCCAAGACCAAG887     LysAsnAlaProAlaGlyGlySerGlyMetAlaSerAlaLysThrLys     240245250     ACGCACTTCTCAGTGAGGCTCCTCAAGTTCTCCCGGGAGAAGAAAGCG935     ThrHisPheSerValArgLeuLeuLysPheSerArgGluLysLysAla     255260265270     GCCAAAACGCTGGGCATCGTGGTCGGCTGCTTCGTCCTCTGCTGGCTG983     AlaLysThrLeuGlyIleValValGlyCysPheValLeuCysTrpLeu     275280285     CCTTTTTTCTTAGTCATGCCCATTGGGTCTTTCTTCCCTGATTTCAAG1031     ProPhePheLeuValMetProIleGlySerPhePheProAspPheLys     290295300     CCCTCTGAAACAGTTTTTAAAATAGTATTTTGGCTCGGATATCTAAAC1079     ProSerGluThrValPheLysIleValPheTrpLeuGlyTyrLeuAsn     305310315     AGCTGCATCAACCCCATCATATACCCATGCTCCAGCCAAGAGTTCAAA1127     SerCysIleAsnProIleIleTyrProCysSerSerGlnGluPheLys     320325330     AAGGCCTTTCAGAATGTCTTGAGAATCCAGTGTCTCTGCAGAAAGCAG1175     LysAlaPheGlnAsnValLeuArgIleGlnCysLeuCysArgLysGln     335340345350     TCTTCCAAACATGCCCTGGGCTACACCCTGCACCCGCCCAGCCAGGCC1223     SerSerLysHisAlaLeuGlyTyrThrLeuHisProProSerGlnAla     355360365     GTGGAAGGGCAACACAAGGACATGGTGCGCATCCCCGTGGGATCAAGA1271     ValGluGlyGlnHisLysAspMetValArgIleProValGlySerArg     370375380     GAGACCTTCTACAGGATCTCCAAGACGGATGGCGTTTGTGAATGGAAA1319     GluThrPheTyrArgIleSerLysThrAspGlyValCysGluTrpLys     385390395     TTTTTCTCTTCCATGCCCCGTGGATCTGCCAGGATTACAGTGTCCAAA1367     PhePheSerSerMetProArgGlySerAlaArgIleThrValSerLys     400405410     GACCAATCCTCCTGTACCACAGCCCGGGTGAGAAGTAAAAGCTTTTTG1415     AspGlnSerSerCysThrThrAlaArgValArgSerLysSerPheLeu     415420425430     CAGGTCTGCTGCTGTGTAGGGCCCTCAACCCCCAGCCTTGACAAGAAC1463     GlnValCysCysCysValGlyProSerThrProSerLeuAspLysAsn     435440445     CATCAAGTTCCAACCATTAAGGTCCACACCATCTCCCTCAGTGAGAAC1511     HisGlnValProThrIleLysValHisThrIleSerLeuSerGluAsn     450455460     GGGGAGGAAGTCTAGGACAGGAAAGATGCAGAGGAAAGGGGAATATCTTAGG1563     GlyGluGluVal     465     TACCATACCCTGGAGTTCTAGAGGATTCCTCGACAAGCTTATTCCGATCCAGACATGATA1623     GATACATTGATGAGTT1639     (2) INFORMATION FOR SEQ ID NO:6:     (i) SEQUENCE CHARACTERISTICS:     (A) LENGTH: 466 amino acids     (B) TYPE: amino acid     (D) TOPOLOGY: linear     (ii) MOLECULE TYPE: protein     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:6:     MetValPheLeuSerGlyAsnAlaSerAspSerSerAsnCysThrGln     151015     ProProAlaProValAsnIleSerLysAlaIleLeuLeuGlyValIle     202530     LeuGlyGlyLeuIleLeuPheGlyValLeuGlyAsnIleLeuValIle     354045     LeuSerValAlaCysHisArgHisLeuHisSerValThrHisTyrTyr     505560     IleValAsnLeuAlaValAlaAspLeuLeuLeuThrSerThrValLeu     65707580     ProPheSerAlaIlePheGluValLeuGlyTyrTrpAlaPheGlyArg     859095     ValPheCysAsnIleTrpAlaAlaValAspValLeuCysCysThrAla     100105110     SerIleMetGlyLeuCysIleIleSerIleAspArgTyrIleGlyVal     115120125     SerTyrProLeuArgTyrProThrIleValThrGlnArgArgGlyLeu     130135140     MetAlaLeuLeuCysValTrpAlaLeuSerLeuValIleSerIleGly     145150155160     ProLeuPheGlyTrpArgGlnProAlaProGluAspGluThrIleCys     165170175     GlnIleAsnGluGluProGlyTyrValLeuPheSerAlaLeuGlySer     180185190     PheTyrLeuProLeuAlaIleIleLeuValMetTyrCysArgValTyr     195200205     ValValAlaLysArgGluSerArgGlyLeuLysSerGlyLeuLysThr     210215220     AspLysSerAspSerGluGlnValThrLeuArgIleHisArgLysAsn     225230235240     AlaProAlaGlyGlySerGlyMetAlaSerAlaLysThrLysThrHis     245250255     PheSerValArgLeuLeuLysPheSerArgGluLysLysAlaAlaLys     260265270     ThrLeuGlyIleValValGlyCysPheValLeuCysTrpLeuProPhe     275280285     PheLeuValMetProIleGlySerPhePheProAspPheLysProSer     290295300     GluThrValPheLysIleValPheTrpLeuGlyTyrLeuAsnSerCys     305310315320     IleAsnProIleIleTyrProCysSerSerGlnGluPheLysLysAla     325330335     PheGlnAsnValLeuArgIleGlnCysLeuCysArgLysGlnSerSer     340345350     LysHisAlaLeuGlyTyrThrLeuHisProProSerGlnAlaValGlu     355360365     GlyGlnHisLysAspMetValArgIleProValGlySerArgGluThr     370375380     PheTyrArgIleSerLysThrAspGlyValCysGluTrpLysPhePhe     385390395400     SerSerMetProArgGlySerAlaArgIleThrValSerLysAspGln     405410415     SerSerCysThrThrAlaArgValArgSerLysSerPheLeuGlnVal     420425430     CysCysCysValGlyProSerThrProSerLeuAspLysAsnHisGln     435440445     ValProThrIleLysValHisThrIleSerLeuSerGluAsnGlyGlu     450455460     GluVal     465     __________________________________________________________________________ 

What is claimed:
 1. A method of screening chemical compounds to identify drug candidates which bind to a human α_(1c) adrenergic receptor subtype on the surface of a cell which comprises contacting a plurality of mammalian cells, wherein each cell comprises a plasmid adapted for expression in the cell, wherein the plasmid comprises DNA which expresses the human α_(1c) adrenergic receptor subtype on the surface of the mammalian cell, with a plurality of compounds, determining those compounds which bind to the human α_(1c) adrenergic receptor subtype expressed on the surface of any such mammalian cell, so as to thereby identify drug candidates which bind to the human α_(1c) adrenergic receptor subtype.
 2. The method of claim 1, wherein in the mammalian cell is a non-neuronal cell.
 3. A method of determining whether a ligand not known to be capable of binding to a human α_(1c) adrenergic receptor can bind to a human α_(1c) adrenergic receptor, which comprises preparing a membrane fraction from a plurality of mammalian cells wherein each mammalian cell comprises a plasmid adapted for expression in the cell, wherein the plasmid comprises DNA which expresses the human α_(1c) adrenergic receptor on the surface of the mammalian cells, incubating the ligand with the membrane fraction under conditions permitting binding of ligands known to bind to the human α_(1c) adrenergic receptor, and detecting the presence of any bound ligand, so as to thereby determine whether the ligand binds to the human α_(1c) adrenergic receptor.
 4. A method of screening chemical compounds to identify drug candidates that bind to an α_(1c) adrenergic receptor subtype, which comprises preparing a membrane fraction from a plurality of mammalian cells, wherein each mammalian cell comprises a plasmid adapted for expression in the cell, wherein the plasmid comprises DNA which expresses the human α_(1c) adrenergic receptor subtype on the surface of such mammalian cells, incubating the membrane fraction with a plurality of drugs, and determining those compounds which interact with and bind to the human α_(1c) adrenergic receptor subtype, so as to thereby identify drug candidates which bind to the human α_(1c) adrenergic receptor subtype.
 5. A method of identifying a ligand which interacts with, and activates or blocks the activation of, a human α_(1c) adrenergic receptor subtype on the surface of a mammalian cell, which comprises contacting a plurality of mammalian cells, wherein each mammalian cell comprises a plasmid adapted for expression in the cell, wherein the plasmid comprises DNA which expresses the human α_(1c) adrenergic receptor subtype, with a ligand, and determining whether the ligand activates or blocks the activation of the receptor, so as to thereby identify the ligand as one which interacts with, and activates or blocks activation of, the human α_(1c) adrenergic receptor subtype.
 6. A method for identifying a ligand that is capable of binding to and activating or inhibiting a human α_(1c) adrenergic receptor, wherein the binding of ligand to the adrenergic receptor results in a physiological response, which comprises contacting a plurality of mammalian cells, wherein each mammalian cell comprises a plasmid adapted for expression in the cell, wherein the plasmid comprises DNA which expresses the human α_(1c) adrenergic receptor, with a calcium sensitive fluorescent indicator, removing any indicator that has not been taken up by the cells, contacting the cells with the ligand, and identifying an increase or decrease in intracellular Ca⁺² as a result of the ligand binding to and activating or inhibiting the receptor, so as to thereby identify a ligand that is capable of binding to and activating or inhibiting the human α_(1c) adrenergic receptor.
 7. A method of determining whether a ligand not known to be capable of specifically binding to a human α_(1c) adrenergic receptor subtype can specifically bind to a human α_(1c) adrenergic receptor subtype, which comprises:(a) contacting the ligand under conditions permitting binding of ligands known to bind to a human α_(1c) adrenergic receptor with a plurality of mammalian cells, each of which comprises a plasmid adapted for expression in the mammalian cell, wherein the plasmid comprises DNA which expresses the human α_(1c) adrenergic receptor subtype; and (b) detecting any presence of the ligand specifically bound to such human α_(1c) adrenergic receptor subtype, so as to thereby determine that the ligand specifically binds to the human α_(1c) adrenergic receptor subtype.
 8. The method of any of claims 3, 4, 5, 6, or 7, wherein the mammalian cell is a non-neuronal cell.
 9. A method of determining whether a ligand not known to be capable of specifically binding to a human α_(1c) adrenergic receptor subtype can specifically bind to a human α_(1c) adrenergic receptor subtype which comprises:(a) separately contacting the ligand, under conditions permitting binding to the human α_(1c) adrenergic receptor subtype by a ligand known to bind thereto, with each of (1) a plurality of mammalian cells, wherein each mammalian cell comprises a plasmid adapted for expression in the cell, wherein the plasmid comprises DNA which expresses the human α_(1a) adrenergic receptor; (2) a plurality of mammalian cells, wherein each mammalian cell comprises a plasmid adapted for expression in the cell, wherein the plasmid comprises DNA which expresses the human α_(1b) adrenergic receptor; and (3) a plurality of mammalian cells, wherein each mammalian cell comprises a plasmid adapted for expression in the cell, wherein the plasmid comprises DNA which expresses the human α_(1c) adrenergic receptor; and (b) determining whether the ligand specifically binds to only the human α_(1c) adrenergic receptor subtype, but not to the human α_(1a) or α_(1b) adrenergic receptor subtype, so as to determine that the ligand is capable of specifically binding to the human α_(1c) adrenergic receptor subtype.
 10. A method of determining whether a ligand not known to be capable of specifically binding to the human α_(1c) adrenergic receptor subtype can specifically bind to the human α_(1c) adrenergic receptor subtype which comprises:(a) separately preparing a membrane fraction from each of (1) a plurality of mammalian cells, wherein each mammalian cell comprises a plasmid adapted for expression in the cell, wherein the plasmid comprises DNA which expresses the human α_(1a) adrenergic receptor; (2) a plurality of mammalian cells, wherein each mammalian cell comprises a plasmid adapted for expression in the cell, wherein the plasmid comprises DNA which expresses the human α_(1b) adrenergic receptor; and (3) a plurality of mammalian cells, wherein each mammalian cell comprises a plasmid adapted for expression in the cell, wherein the plasmid comprises DNA which expresses the human α_(1c) adrenergic receptor; (b) separately incubating the ligand with each of the membrane fractions prepared in step (a) under conditions permitting binding to a human α₁ adrenergic receptor subtype by a ligand known to bind thereto; and (c) determining whether the ligand specifically binds to the membrane-bound human α_(1c) adrenergic receptor subtype, but not to the membrane-bound human α_(1a) or α_(1b) adrenergic receptor subtype, so as to determine whether the ligand is capable of specifically binding to the human α_(1c) adrenergic receptor subtype. 